


There Are No Genes for Fate

by lily_winterwood



Category: Gattaca (1997), Sherlock (TV)
Genre: Alternate Universe - Fusion, Alternate Universe - Science Fiction, M/M, References to Suicide, Reichenbach Falls, Suicide, Suicide Attempt
Language: English
Status: Completed
Published: 2012-06-05
Updated: 2012-06-06
Packaged: 2017-11-07 00:49:49
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 11
Words: 22,420
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/425115
Author URL: https://archiveofourown.org/users/lily_winterwood/pseuds/lily_winterwood
Summary: <blockquote class="userstuff">
              <p>It’s as if the past few years of building his reputation as the most accurate and merciless Identifier in London don’t count, because the instant John Watson stepped into his life he had turned it upside-down. With one little lie, Sherlock finds his entire world crumbling at the edges. Gattaca/Sherlock AU.</p>
            </blockquote>





	1. ATG (METHIONINE)

**Author's Note:**

> BBC Sherlock belongs to the Mofftisson and co, Sherlock Holmes belongs to ACD and co, Gattaca belongs to Andrew Niccol. This fic was inspired in part by Candle Beck’s “[The Beauty of the Dark](http://www.fanfiction.net/s/1645859/1/The_Beauty_of_the_Dark)”, a hauntingly beautiful Vincent/Jerome fic that everyone needs to read already, and also in part by [Michael Nyman’s amazing soundtrack](http://www.youtube.com/watch?v=TXeBe2XQDZg&feature=results_main&playnext=1&list=PL0320AFAAE5B71D77).

* * *

A naked man sits inside a giant, cylindrical chamber, clipping away his fingernails and toenails, brushing away excess hair, scrubbing away loose flakes of skin. He stares up at the cold fluorescent light and shivers in the semi-cold.

The man clambers out of the cylinder moments later, presses a button, and watches the flames rise up within the chamber, destroying all evidence of his presence. The ruddy glow of the fire flickers across his face, the flames dancing across his murky brown eyes, across his golden hair. They highlight two bright scars just below his knees, and caress his well-built body.

He gets dressed in a clean blue suit with a striped tie and combs his hair across his head before straightening up, trying his best not to squint at his reflection – it’s a bit blurry; he has myopia, after all. He crosses over to the sink and inserts his colour contacts; they tint his eyes dark cerulean.

Fingerprint pads are next, their satchels filled with blood from a nearby incubator. A pouch of urine sits gartered to the man’s legs, hidden beneath his trousers. More blood sit in phials tucked away inside the man’s suit, along with a handheld duster and several more phials of skin and hair.

When this man shows up at St. Bartholomew’s Hospital, the scanners identify him as Sebastian Moran, a successful surgeon with an IQ off the charts, nerves of steel, and longevity predicted to extend well past his hundreds, possibly even forever. He waves hello to the doctor in charge of security screenings, a woman named Molly Hooper. She smiles at him as he vanishes into the lifts.

Little does she know that he is actually not Sebastian Moran.

* * *

The body is discovered in the same corridor as the consultation rooms. He is identified as William Murray, director of the hospital. Barely anyone mourns his passing, least of all the teachers. He won’t be missed.

Bill Murray has been killed by a blow to the back of the head by a keyboard from the computer lab on that level. The Yard hoovers the entire room and the adjacent corridor, and begins their investigations. With them is an exceptional man by the name of Sherlock Holmes, called into the investigation for only one purpose.

Sherlock is an Identifier.

This is a world where every human can be boiled down to a simple sequence of four letters. From their moment of birth, their future is set. If they possess traits only available to enhanced – genetically perfect – embryos, there will be no door closed to them. But if they are not so fortunate – if they are a faith birth, a child whose genes are left to chance, not science – they become second-class citizens. In-Valids, relegated to menial labour.

Only the most desperate of the in-Valids would commit the ultimate crime. Only they would steal, steal the genetic identity of another. Only they would refuse to play the hand dealt to them and become borrowed ladders.

Sherlock’s job is to find those borrowed ladders.

He has all of the genes for the job. His eyesight is keen, astute. His mind races faster than a rocket. He is capable of deducing the birth status and occupations of everyone he meets with a single sweep of his eyes. He could have gone on to become something far greater, but he chose to be an Identifier. So the Yard calls on him to come along to high-profile cases, to weed out any borrowed ladders within the suspects. After all, borrowed ladders have unaccounted-for genetic material, and thus pose security risks.

Or at least, that is the cover story. The belief underlying that is that the perpetrator is usually a borrowed ladder. Genoism may be illegal _de jure_ , but in practice that is never the case. Genoism flourishes, and Sherlock Holmes is the sniffer dog of the genoists.

Sherlock Holmes examines Murray’s body with the rest of the Yard from his place next to Detective Inspector Lestrade. As the police begin to queue the hospital workers in the corridor, Sherlock gets to work. He paces up and down the ranks of doctors and nurses, scanning each and every one of them with his eyes.

He pauses when he gets to a man with golden hair and dark blue eyes.

* * *

This man is actually named John Watson, an in-Valid conceived by accident in the back of a Ford Anglia in Surrey. His older sister, Harry, is the one born naturally – born enhanced.

Well, the geneticists forgot to remove the alcoholism gene with her… but that’s of no import because right now, John is standing under the mask of Sebastian Moran, staring defiantly back at the keen eyes of Sherlock Holmes.

His heart – diagnosed at birth with cardiac arrhythmia – beats erratically in his chest, and he’s pretty sure Sherlock can hear it. As the Identifier’s eyes trail down his body, John feels the first palpitations of sweat. He’s pretty sure Sherlock can make out the outline of the urine pouch hidden beneath his trousers; pretty sure Sherlock has seen the shadows of the blood packets underneath his thumbs. He’s pretty sure the hospital light is making his contact-shielded eyes shine into Sherlock’s line of sight. He’s seen Sherlock at work before. Just the other week, he had observed on his nightly jog Sherlock accompanying DI Lestrade as he arrested a borrowed ladder in the government. The man, Andrew West, had actually been an in-Valid man named Joe Harrison.

John wants to close his eyes and resign himself to his fate, but suddenly Sherlock breaks eye contact and steps down the line. John exhales, long and slow. Hopefully disaster has been averted, however temporarily.

For almost as long as he remembered John has wanted to be a doctor, a surgeon. The human body interests him; he wants to take apart and fix this strange apparatus; he wants to discover the secrets of human life. It’s only fitting that an imperfect man like himself would want to understand his own imperfections. But unfortunately for him the doors are closed.

John trained in secret. No med school would accept him as an in-Valid, but he did manage to find a retired surgeon sympathetic enough to train him to become one as well. For the first few years of his life outside of home, then, John spent his workdays scrubbing toilets and performing manual labour at wherever his current job was, and his nights studying medicine and practicing his techniques.

But as skilled as he is, the instant any potential employers saw his genetic record it would be a lost cause. Even if he didn’t disclose, there would be other ways to illegally procure his genetic profile – through a drugs test, a fingerprint, a loose fleck of skin or hair. Who wants a surgeon with terrible eyesight, a surgeon with a nervous heart condition, a surgeon with a genetic profile inferior to those of his peers? All he can do as John Watson is scrub the toilets and wipe the glass, and for years he did just that at St. Bart’s. Through the glass windows looking into the operation room, John watched the surgeons at work and wished that he could do the same. After all, there is nothing more disheartening about an unattainable dream than standing right in front of it, separated only by glass and air.

And then John met James Moriarty, the Forger. He was, at that point, too desperate to question Moriarty’s motivations. It didn’t seem important, because with a single introduction Moriarty opened a closed door. The man whose identity John would assume was a man named Sebastian Moran, an Afghanistan war veteran who had been wounded in the shoulder and legs. The leg injury confined him to a wheelchair; the shoulder injury only pained him occasionally. Moran lends John his body, his identity, and under his mask John is thus able to become the best surgeon at Bart’s. After all, he’s already done the training in secret. All he needed was the blood test.

Now all of that is crashing around his ears with a single glance from Sherlock Holmes, and John feels resentment curl in his stomach. He watches Sherlock finish his circuit and stride back to the police, shaking his head.

John closes his eyes.


	2. TGC (CYSTEINE)

“Well?” Lestrade asks as Sherlock returns to his side. Sherlock shakes his head.

“Nothing,” he says, but of course that’s a lie. He’s seen the surgeon with the cerulean eyes. That man is no Valid. His skin is still raw from his morning exfoliation; his heart is beating far too erratically for a Valid; his eyes shine from where his contacts catch the light. No, Dr Moran is a borrowed ladder, but Sherlock isn’t inclined to squeal today. He may work with the Yard, but he doesn’t have to answer to them.

(Besides, Moran is irrelevant to the case. He’d just gone through morning urine screening, if the unzipped fly is of any indication.)

“All right, then.” Lestrade gestures to the body. “We’ll double-check with the usual tests; I’ll have Miss Hooper tend to that.” With that, he waves away the doctors and nurses assembled; they disperse and Sherlock finds himself turning to watch Dr Moran vanish into his consultation room.

He sighs and looks back down at the body, saying, “Murray was killed leaving the lab, from behind. We know that he’s unpopular with the teaching staff, and that the killer was probably in the lab with him before his death.” He pauses, frowning at the body.

“Take a look at this,” Anderson says suddenly. Sherlock rolls his eyes as Lestrade walks over to him. “The eyelash of an in-Valid.”

“Sure that’s not yours, Anderson?” Sherlock sneers. But Anderson holds up the scanner screen, with the face of a bespectacled young man on it. JOHN WATSON, it reads. IN-VALID.

Sherlock raises an eyebrow. “I see.”

“John Watson. Know him?” Lestrade asks, but Sherlock shakes his head.

“The files will tell, though. I’ll see if Mycroft has them.”

* * *

Mycroft Holmes relinquishes the employment logs of Bart’s after Sherlock reminds him that he caught Mycroft’s own personal assistant as a borrowed ladder last week. Andrew West has since then been replaced by a woman named Anthea. Sherlock ignores her as he exits the office with the files.

John Watson had been, according to the files, employed at Bart’s as a cleaner around five years ago. He then disappeared. The records of in-Valids and Valids are kept separate, but Sherlock is fairly certain that if he bothered to look through the Valid files he would see Sebastian Moran’s name emerge five years ago, around the time John Watson disappeared from Bart’s.

He only tells Lestrade the first part, though, and quickly signs off, heading for his usual chemical laboratory at the hospital. Molly Hooper is running the daily screenings. Sherlock notices that the borrowed ladder has evaded capture that way and smirks.

At that moment, however, the door to the lab opens and Dr Moran walks in, smiling at Molly.

“I’m here to get my results for Ms Irene Adler,” he says.

“She’s not entirely Ms Adler,” Sherlock says as he stoops over the microscope in an attempt to look busy. He hears Moran’s footsteps halt; grinning to himself, he straightens up and fixes the borrowed ladder with his steely gaze.

“Not entirely… Ms Adler?”

“The databases show that she is, yes, but she was also part of a borrowed ladder arrangement with a woman named Kate,” Sherlock answers calmly. “I caught them after a prominent novelist came to me asking to sort out an affair of hers.”

“Oh.” Moran smiles blandly. “I thought the donor usually stays out of sight, though.”

“I never said _she_ was the donor.” Sherlock doesn’t break eye contact.

Moran shifts uncomfortably. “So you’re the one responsible for sending her to prison. She never told me what for.”

“Fraud, obviously.” Sherlock shrugs carelessly. “Of course her donor bailed her out. Others haven’t been as lucky.”

Moran definitely looks uncomfortable at this point as he takes his results. “Well, that’s, uh, good to know.” He smiles briefly, backing towards the door. “Thank you.”

Sherlock watches him leave with an odd dryness in his throat.

* * *

John exhales long and slow as soon as he reaches the sanctuary of his office. He dusts the room, hoovers away as much evidence of John Watson as he can before replacing it all with traces of Sebastian Moran. The results for Ms Adler’s tests he tucks away into her file. She’ll be arriving for their appointment tomorrow, but in the meantime he has to go home to check up on Sebastian –

He runs into Sherlock in the hallway outside. His breath hitches sharply; his traitorous heart is beating wildly. Sherlock advances towards him, eyes still scrutinising and sharp as ever. John wonders what sort of colour they are; with every flicker of light they change.

“They’re supposed to be silver,” Sherlock explains as if he can read John’s mind (and at this point, John wouldn’t be surprised if he could). “From my mother.”

“Oh.” John nods. “Did you want something?”

Sherlock says nothing, only gestures for John to follow him down the hall. They walk in silence out of the hospital; once out, Sherlock hails a cab.

“Where to?” he asks John. John blinks.

“Montague Street,” he says after a moment.

Sherlock nods; the cab drives off. John watches Sherlock warily from his seat, but Sherlock serenely stares ahead.

“What are you doing?” John asks, trying to break the silence, trying to assuage the tremulous fear that seizes at his heart.

Sherlock looks at him sidelong, the corner of his mouth twitching into a smirk. “I know,” he says after a moment.

John’s shoulders slump slightly. “Know about what?”

“You’re actually John Watson, aren’t you?”

“Why would you say that?” John asks, still hoping against hope to bluff his way out of this. Sherlock doesn’t look as if he has a scanner on hand, after all.

“Because records show that John Watson disappeared from Bart’s around the same time Sebastian Moran appeared. One an in-Valid, the other a Valid. Couple that with your similar features and the obvious signs of alteration of yours to fit his and… well, it’s not hard to make the leap.”

John slumps fully, resigned. “You told the Yard, didn’t you?”

“Not a word.”

That throws him for a curve. John bolts upright, turning to Sherlock.

“You…”

“Didn’t tell the Yard,” Sherlock replies.

“But why?”

They arrive at Montague Street. Sherlock beams at him, saying nothing as John reluctantly gets out of the cab.

“I should probably pay,” he says, trying to stall for time, for explanations. “Reimburse you –”

“It’s fine,” Sherlock replies. “Baker Street!” he snaps at the in-Valid cabbie.

The car zooms away from the kerb, leaving John gaping after it. A couple moments later, he turns tail and enters his and Sebastian’s flat. Sebastian is in his wheelchair in the basement, smoking like a chimney as he fills bags upon bags with blood and urine.

“Make sure you don’t pull the whiskey piss stunt again,” John snaps at Moran as he enters the basement via spiral staircase. “I’d have gotten dinged for that, if the screening hadn’t been after lunch.”

Sebastian rolls his eyes and blows smoke in John’s face. John wrinkles his nose, wafting the foul smoke away from his face.

“Will you stop doing that?”

“You’re not the one cramped in a basement,” Sebastian points out drily.

“If you’re so keen on getting out, why don’t you?”

“You know full well they’ll be suspicious. Especially with a bloke like Holmes flitting around outing every borrowed ladder he can get his eyes on –”

“Holmes was at Bart’s today.”

At that, Sebastian raises an eyebrow.

“Come again?”

“Holmes. Was. At. Bart’s. Today.”

“Oh god,” sighs Sebastian, rubbing his temples. “Please tell me he didn’t see you.”

“He did.”

“Jesus, John.”

“You must be agitated to call me that.”

“Yeah, hearing that my in-Valid’s gotten himself caught by Holmes –”

“He didn’t report us, Hamish.” They’d agreed, years ago. The instant John secured the job at Bart’s, he would be Sebastian. And Sebastian would be Hamish, John’s middle name. John had to, after all, get used to being called Sebastian.

“He didn’t – is this the same Holmes we’re talking about?”

“Holmes the Identifier? Yeah. Same bloke.” John crosses to the sidebar and pours himself a glass of brandy. Sebastian keeps a varied liquor cabinet, after all. “He told me he didn’t tell the Yard about us. Don’t know why, though.”

Sebastian snorts. “Luck of the Irish, perhaps,” he drawls sarcastically. John can tell he doesn’t buy it.

He plays along. “I’m Scottish.”

“Well, I’m Irish and that’s my name you’re using.” Sebastian grins cockily at John and takes another drag of his cigarette. “Wanna go dancing?”

“Like you could manage with your wheelchair.”

Sebastian snorts. “You’re no fun.”


	3. TAC (TYROSINE)

John Watson’s face is plastered all over the boards the next day, though. He fastidiously avoids the part of the floor where the murder has taken place, and tries to spend as much time cooped in his office as possible.

Sherlock arrives in his office after lunch. “They think you killed the director,” he says by way of greeting.

“What?” John asks stupidly, frowning.

“Don’t be dull, _Moran_ ,” Sherlock intones, inflecting the last word with sarcasm. “The Yard thinks an in-Valid named John Watson is Dr Murray’s killer. Former cleaner at Bart’s, disappeared years ago? That doesn’t matter. Apparently they found an eyelash of his in the same corridor, just outside the computer lab.”

“Could be old,” John suggests weakly.

“You know what it’s like. The floors here are hoovered and scrubbed until you could use them as mirrors. Would any cleaner at Bart’s allow for an eyelash to stay undetected for five years?”

John chuckles. “Well, if you put it that way…”

Sherlock crosses his legs and steeples his fingers. “Personally, I’d like to know what it is about you that compelled me to lie for you. After all, at first glance you are exceedingly ordinary-looking, and yet…” he trails off, scowling.

“Yet?”

“Yet there’s something different here about you. Something good.” Sherlock’s eyes narrow. “Tell me. Why would you want to put your neck on the line by becoming a surgeon at one of London’s most prestigious hospitals? Most doctors I know are in it for the money and the security, whatever security there may be in dying people.”

John looks down at his hands. “Not sure, really,” he says quietly. “Service? Danger? Something like that. I’ve always been interested in the human body. I want to save lives.”

Sherlock nods, looks at John for a very long time (as if his previous stares hadn’t been long enough). “I see,” he says after a moment.  

“Oh,” John says simply, and for a moment all he can hear is the heavy thudding of his own heart.

Sherlock’s hand slips across the desk, ghosting against the tips of John’s fingers. The Identifier nods, smiles briefly, and turns to leave. On the way out, however, he adds, “Come to 221B Baker Street at nineteen hours sharp. I could use your expertise.”

With that, the door slams shut and John stares at it long after the fact, playing over Sherlock’s message in his head with a frown. What sort of expertise would Sherlock need? And why him?

By half-eighteen John is already chafing to leave. However, Molly is doing additional screening on the way out, and John watches the stacks of unused urine sample cups dwindle on the counter in the screening room.

He dribbles out a half-cup of Sebastian’s piss, and prays that it’s not a sample with alcohol in it.

* * *

“It can’t be Watson,” Sherlock snaps at Lestrade. They’re sitting in 221B Baker Street; it’s taking all of Sherlock’s willpower not to throw his teacup at the wall. Lestrade is being obstinate; he somehow thinks that Watson is responsible for a crime that he obviously has no connections to, masquerading as Moran or not.

Of course, Sherlock cannot prove it fully without giving John away. He taps at the armrest of his chair and glares at Lestrade, before pulling out another set of papers.

“Look here,” he says. “These are the records of various borrowed ladder arrangements. They’re all connected – components of their disguises come from similar places. The contact lenses are all manufactured in the same plant. That plant is managed by a man named Roylott, who in turn is connected to –”

“James Moriarty,” murmurs Lestrade, looking at the records with a roll of his eyes. “Your infamous Forger.”

“Exactly. Moriarty is at the centre of a borrowed ladder network. His connections extend far and wide, yet many pairs in the web are unaware of his presence; for them there is rarely direct contact. Now, I believe that Moriarty may have had a hand in the death of Dr Murray. You see, Murray’s sister was a borrowed ladder.”

“What?” the teacup pauses on its way to Lestrade’s lip. The DI frowns at his beverage and sets its cup back onto its saucer. “You can’t be serious.”

“Amanda Murray,” Sherlock replies, shuffling through the pile and holding up one of the papers, “was an in-Valid who once worked near the United Kingdom branch of the Gattaca Aerospace Corporation. Cleaning loos wasn’t her dream job, so she disappeared. And within that year, Gattaca UK accepted a talented young engineer named Soo Lin Yao.”

Lestrade raises an eyebrow. “Soo Lin Yao? Really?” he demands incredulously.

“Murrays have some Asian heritage. It wasn’t too hard to make the leap. During Soo Lin Yao’s tenure at Gattaca UK, traces of Amanda appeared in the corridors. She became the ‘ghost of Gattaca’, the slips in security that needed my help to patch.” Sherlock smirks, closing the file. “I caught her, of course. Thus, Moriarty is connected to the Murrays. He’s connected to Dr Murray’s death by only the slightest margin.”

“But what happened to his sister?” Lestrade demands.

“That’s irrelevant.”

“You can’t just leave off with you catching her.”

“She committed suicide a week later with her donor. Wasted talent,” sniffs Sherlock, sipping his tea.

At that moment, the buzzer sounds. Mrs Hudson fetches it; she is an in-Valid whose equally in-Valid husband had been executed in Florida for murder. But then again, his genetic profile had suggested an aggressive disposition. Sherlock had assisted in convicting him; apparently Mr Hudson had gone into hiding as a borrowed ladder. Still, the money he had managed to make as a Valid had passed to her, and she had used it to buy 221B. Now she is the landlady of the house, letting out the upstairs flat to Sherlock for his services. After all, she hadn’t liked being cuckolded.

John Watson – Dr Sebastian Moran – appears at the upstairs landing moments later, smiling nervously at Sherlock at Lestrade. Sherlock gets up, shakes John’s hand, and ushers him inside.

“Detective Inspector Lestrade, meet Dr Moran,” Sherlock introduces as John briefly shakes Lestrade’s hand and takes a seat on the sofa adjacent to their armchairs.

“Nice to meet you,” Lestrade remarks over a sip of tea.

“Tea?” Sherlock asks pleasantly. John smiles and nods as Sherlock pours him a cup.

“Thanks, Mr Holmes.”

“Sherlock, please.” Sherlock takes a seat and steeples his fingers. “Now, about the murder of the hospital director.”

“He won’t be missed,” John replies, expression serious but eyes amused. “He was trying to cut the teaching programme.”

“Is that a popular programme at the hospital?” Lestrade asks.

“Obviously.” John smiles. “The one at Bart’s is unparalleled, you see. I myself was trained there.”

The slight upward twitch of Sherlock’s mouth suggests that he doesn’t buy it, but Lestrade doesn’t notice.

“What about their hiring policies?”

John frowns as he sips his tea. “I don’t know if I have the clearance to answer that, sir.”

“You are their best surgeon. Tell us what you think,” Lestrade offers, and Sherlock vaguely wonders why John’s light pink blush is so bloody _endearing_.

“Well, thank you.” John looks down at his cup, beaming sheepishly. “And, well, deputy director Stamford always says that they take on only the best, the _crème de la crème_ , the people with the highest potential. Many of our doctors could just as easily be medical researchers for Gattaca.”

“Potentials?” echoes Lestrade, frowning. “Does everyone meet their potential at Bart’s?”

“Well, Stamford always says no one exceeds them.”

“Really? That’s a bit cruel,” mutters Sherlock. John shifts nervously in his seat, eyes flickering to Sherlock as if to ask why he’s being bombarded with questions.

“Well, it’s what Stamford says,” he says after a moment. “If someone does exceed their potential, then that means we didn’t measure their potential right in the first place.”

Lestrade nods, jotting everything down. “Thank you, Dr Moran.” He clambers to his feet to leave. “We’ll keep that in mind for our motives.”

After the DI leaves, Sherlock produces a long roll of paper. He watches the expressions flitter across John’s face – confusion, fear, anxiety – before unfurling it.

“Results of testing from the eyelash,” he says by way of explanation. “Cardiac arrhythmia and myopia?”

John nods, bowing his head. Sherlock launches himself out of his seat and to John’s side, tossing the papers away and peering at him anxiously.

“Does it matter?” he asks.

“You tell me,” John replies sullenly. “For all my life I have been the unwanted kid. The stupid faith-born child. The mistake. You tell me if it matters to me, having my genetic identity smeared in my face for as long as I can remember.”

Sherlock looks down at the in-Valid’s hands. He takes them, examines the fingertip pads with their blood sachets hidden beneath. He looks up again, peers into John’s eyes and wonders what colour eyes John has underneath those cerulean contacts. He wants to know, but now is hardly the time to ask.

Instead, Sherlock reaches up and plucks out a strand of his own hair. “Predisposition to addictive substances, especially cocaine. I may be Valid, but I am far from perfect.”

John takes the hair. Sherlock watches him hold it up to the light.

He takes John’s hand, eyes pleading. “Does it matter?” he asks again, voice barely above a whisper.

John smiles, and lets the hair blow away. “No,” he says after a moment. “It’s all fine.”

* * *

Sebastian looks at John accusingly as the other descends the spiral staircase. “Dinner’s gone cold,” he remarks acidly.

“Not like it concerns you.” John replies. “You barely eat. You need to.”

“Don’t feel like it.” Sebastian wheels himself up to John, peering at him curiously. “Seen Holmes, have you?”

“What?”

“Don’t play stupid with me, _Sebastian_.”

“How would you know, _Hamish_?”

“You’re the first person he’s ever lied for. If you think that makes you special, think again.”

“So what?” Despite what’s tumbling out of his mouth, John can’t help but feel a surge of something deep within him – some strange satisfaction about the idea that _he_ is the first person Sherlock Holmes has ever lied for. “I don’t care. I don’t care about Sherlock Holmes.”

“You should,” Sebastian had been wheeling himself back down the rows of chemical equipment; at that he spins around to face John again. “He’s not on our side. He works to expose people like us. If you let him get to you, it will only make that inevitable betrayal so much worse.”

John stares at his donor, rooted to the spot.

Sebastian turns back and heads for the storage room, where he’s archived a full week’s worth of genetic data. “Stay away from Sherlock Holmes. Trust me.”


	4. ATT (ISOLEUCINE)

Mike Stamford is treating John to lunch at the Criterion. There are whispers about him, Dr Sebastian Moran, getting a well-earned promotion. John wouldn’t have been surprised at this rate; he is, after all, the best surgeon at Bart’s.

What concerns him more, though, is the pressing worry over his patient Irene Adler. She didn’t show up to her appointment the day before yesterday, and all he gets when he calls is her donor, Kate. Kate constantly says that Irene is busy, but John highly doubts that. Irene has never missed an appointment.

“So, Sebastian! Another year of hard work, aye?” Stamford asks jovially over a glass of wine. John smiles, inclines his head in thanks.

“Pleasure’s all mine. It’s quite the privilege to work in such a historic hospital,” he says. “My condolences about Murray, though. Thought you two might have had a close working relationship.”

“Never closer.” Stamford grins, looks down at his glass. “Though I’ve been teaching a bit these past few days. Bright young things, those med students! God I hate them.”

John laughs. “Burden of perfection.”

“Aye.” They clink glasses; John gingerly sips at his glass and hopes that the salivary substitutes are convincing enough, should the police barge in.

“The investigation, how’s that going along?” he asks as the waiter comes by with their food. Stamford raises an eyebrow.

“Ah, hard on all of us, isn’t it? Extra screenings, spot checks. Enough to make us all wonder if they’re actually searching for Watson or if Holmes has just brought over his crackpot idea that every prestigious institution’s being infiltrated by borrowed ladders who’re being controlled by some lunatic. I’m sure there’s plenty elsewhere, but it’s not like they’re all out to kill us Valids. Yet.”

“Well, I guess they’ve, er, come into style since the incident at Gattaca,” John reasons, remembering the Freeman-Morrow debacle over in the States a couple years back. Apparently upon the death of one of their finest astronauts, it had been revealed that the man, Jerome Morrow, had actually been a borrowed ladder named Vincent Anton Freeman. The scandal had almost been repeated with Amanda Murray and Soo Lin Yao over on this side of the pond, but Sherlock had hushed it all up quite nicely.

In conjunction with Moran’s warnings, it’s enough to send shivers down John’s spine.

“Yeah, well. Dunno if my brother ever had the guts to do it,” Stamford says after a moment, breaking John’s musings. He looks up, eyebrows raised. Stamford chuckles. “Didn’t I ever tell you? I had an older brother who was an in-Valid. Jeff Hope, he was called. Not much hope for him, though. Mum and Dad died thinking they outlived him, since he disappeared several years ago, around the time the Freeman-Morrow scandal surfaced Stateside.”

“Poor sod. What’d he have?”

“Asthma, type 1 diabetes, high chances of kidney failure. And that’s not even taking into account his risk of getting an aneurysm. Think he did get one. Last time I saw him, he was a cabbie.”

“Wow.” John raises an eyebrow and sips his wine again. “Yeah, it’d be quite the miracle if he is still alive.”

“Yeah, you bet.” Stamford finishes his glass of wine with a smack of his lips. “We better finish lunch soon, before Molly has our heads for missing the screening window.”

When they get back to the hospital, Molly is there with hypodermic needles and a distinct air of unease about her.

“Sorry boys,” she says as Stamford takes a seat across from her, arm on the table. “Intravenous blood sample screenings this time around. Police aren’t taking any chances.”

John pales a bit, but locates the phial of blood within his trouser pockets and sighs. He shoots a furtive glance at Lestrade, who is standing next to Molly with his eyes trained on Stamford.

Stamford checks out with nothing more than a slightly high blood-alcohol ratio, obviously, but when it comes to John’s turn he is buzzing with nerves. Molly locates the vein in the crook of his elbow and inserts the needle; John conceals the phial of Moran’s blood in his hand and waits for her to start drawing blood.

Once she begins to, though, he lurches forward and flexes his arm, causing the needle to buckle and bend, exiting through a second puncture point. He cries out in pain; Molly leaps away in shock, eyes horrified.

“Ow! Mind what you’re doing with that needle!” John cries, fighting his instincts to apologise as soon as he sees the tears starting to form in the corners of her eyes. Slowly he reaches down to withdraw the bent needle, spraying blood all over Lestrade’s shoes.

“Oh god, this has never happened to me before, Seb, I’m so sorry!” she blusters, lurching forward to try and bandage his arm. Lestrade grabs a piece of gauze to wipe the blood off his shoes. With the DI distracted and Molly peering anxiously into his face as she bandages his arm, John hastily swaps the phials of blood in the syringe and tucks his own away into his pocket. Out of the corner of his eye he notes with satisfaction that Lestrade has disposed of the incriminating gauze.

Molly’s expression is apologetic as she takes Moran’s sample and scans it. Obviously it passes the test. “God, I’m so sorry…”

“Just… don’t let it happen again,” John sighs, trying to make his eyes appear as apologetic as possible as he shuffles from the room. “No… no harm done, Molly. All right?”

She nods, but her smile doesn’t reach her eyes. John leaves the room with Stamford, who shakes his head as soon as they’re out in the corridor, out of earshot of Lestrade and Molly.

“Odd, isn’t it?” the deputy director remarks.

“Yeah, very,” John sighs.

* * *

On the way to Bart’s, Sherlock sees several policemen rounding up some people in the in-Valid quarter of London. Frowning, he stops the cab and tells the driver to wait as he walks up to the chain-link fence and slips through the security checkpoint.

The in-Valid quarter is a seedy corner of London that Sherlock would much rather not set foot in, but occasionally he has, out of necessity for his cases. The haunted, accusing looks of the in-Valids peering out of their windows and doors unsettle him, to say the least. He’s tried to delete the haunted looks on their faces after each case that takes him through their territory, but each new case brings them back to the forefront. It’s disconcerting and annoying at the same time.

After all, to the in-Valids Sherlock is a dream-crusher, a life-ruiner. As he walks up to the line of in-Valids, he feels for a moment the pangs of guilt, disconcertingly juxtaposed with John’s beaming face. He looks so much in his element at Bart’s. Sherlock would hate to destroy the happiness in his eyes.

“What’re you doing here, Freak?” Sergeant Sally Donovan asks as Sherlock looks around him at the rounded-up in-Valids. They all sport glasses and dishwater-blond hair, but obviously none of them are John Watson, not even the John Watson in the identification picture.

“I might ask the same for you,” Sherlock drawls, looking warily at the in-Valids. They have been isolated from Valid society with fences and chains. When treated like prisoners and dogs, they will only revert to prisoner-like and dog-like behaviour. It’s a self-fulfilling prophecy. “Watson can’t be here. What the hell are you doing?”

“Orders from Lestrade. Got to cover the bases.”

“Watson’s got nothing to do with Murray’s death. Lestrade’s following a false lead like always, the useless fool.”

Donovan snorts. “Yeah, and which hard-working Valid is going to get exposed as a borrowed ladder today, Freak?”

“Well, if a borrowed ladder killed the director, hypothetically speaking, he wouldn’t be hiding in here. He’d be out of the in-Valid quarters, roaming our streets. Why in the world would he return to where he started if he can go anywhere else?”

“Are you saying that –?”

“That was a hypothetical situation. Now, in the case of Dr Murray. Watson’s DNA is only on an eyelash found several metres from the crime scene. I guarantee you that the killer left his or her DNA on Murray or the instrument used to kill Murray. Instead of looking for an in-Valid who’s lost an eyelash, why don’t we test for foreign saliva in the eyes of the victim? Instead of searching in places where any self-respecting borrowed ladder would avoid like the plague, why don’t we search where the borrowed ladder would be in the first place? Bart’s, perhaps?”

Donovan shakes her head. “Piss off, Holmes.”

“I’m just making up for the brains that didn’t get coded for by the rest of Scotland Yard,” sneers Sherlock as he turns tail and leaves the quarter, trailed by the accusatory gazes of half a dozen in-Valids.

* * *

John looks up from Irene Adler’s test results as Sherlock enters his office. “Oh, it’s you,” he remarks mildly, setting down the results. “What can I do for you?” Despite the rather cool tone, he’s actually rather pleased to see Sherlock, if not downright excited and happy. It must show in his smile, in the warmth of his eyes.

“Come with me,” Sherlock says imperiously, popping up the collar of his coat. “We have to go to the bank.”

“What for?” John asks. “I’m working.”

“Your next patient won’t be in until half sixteen.”

“I won’t be of any use to you.”

“No, but I’ve got a theory to test and I was hoping you have some information for me. Do you know about Sir Jeffrey Patterson?”

John frowns. “No… is he important?”

“Very,” Sherlock replies. “They say he just returned from a trip around the world, his second in a month. He’s some kind of bank manager, very high up, close to an old friend of mine. Well, Wilkes says he’s been acting odd lately, so I need –”

“You need to find out if he’s been replaced by a borrowed ladder,” John finishes. He nods, standing up. “Not sure why you’d need my help, especially since it’s one of my people you’ll be outing.”

But in the end John follows Sherlock to the Strand, to the forty-second floor of a bank where a man named Sebastian Wilkes shows them to the trading floors. “Patterson’s in the office over there,” he says, pointing to an office with frosted glass walls. John rather dislikes the superiority wafting about Wilkes, but he makes no comment.

Sherlock absolutely ignores the other man, despite his earlier statement that Wilkes had been an old friend.

Within seconds of entering the office, Sherlock nods in affirmation. “Yes, you’re the one,” he says, taking a seat. “A borrowed ladder of Sir Jeffrey Patterson. Wonderful.”

The borrowed ladder looks up in alarm. “Who told you?” he demands, springing from his seat in an attempt to get to the door. Sherlock is at the door in a flash, arms spread to prevent the borrowed ladder’s escape.

Sherlock points to the blazer hanging on the coat rack behind his desk. “Inside lining suggests you use the inside right breast pockets to keep traces of your donor’s DNA, which suggests that you favour your left hand. Yet judging by the placement of his notepad in relation to the phone and his pencil holder in relation to the computer, Sir Patterson is right-handed.”

“Ah.” The borrowed ladder grits his teeth. “Bet you can’t guess my real name, though.”

“I never guess.” Sherlock smiles dangerously, and John shudders in fear at the utter cruelty of that shark-like smile. “Just tell us. It’ll be a quick, painless procedure that way if you choose to cooperate.”  John looks down at the desk. “What is your real name?”

“Jeff Hope Stamford,” replies the man. John looks up again, eyes wide.

“Wait a sec. You’re him? Mike was just talking about you!”

The in-Valid’s eyes narrow. “My brother was talking about me?” he growls.

“Yeah, he thought you were dead or something. Said it’d be a miracle if you were still alive.”

“I exist on borrowed time,” Jeff replies, rolling his eyes. “Outlived my parents, I seem to have. Hah, that’ll show them.”

John smiles a bit, looking down again. After a moment he looks over at Sherlock, who is still analysing Jeff as if he is a particularly puzzling case. Being a borrowed ladder isn’t a new idea, obviously. But with the success of Vincent Freeman, anything had become possible. The majority of Valid society tended to turn a blind eye to most borrowed ladders as long as they kept to themselves and stayed productive, and John has more than once heard about near-escapes and help from sympathetic Valids.

But all of that is changing now, with Moriarty restoring the criminal aspect to being a borrowed ladder. With control of Valids and in-Valids bound together by the borrowed ladder arrangement, Moriarty has the power to rule England. Every pair under his sway has no choice but to obey his orders if he ever chooses to use them.

John feels dread settle in his stomach. Does Sherlock know that he, too, is part of Moriarty’s web? But he doesn’t dwell on that for long, because the ringing of his mobile breaks the tense silence. It’s Molly, her voice frantic.

“Sebastian, where are you?” she demands. “Detective Inspector Lestrade’s looking for you!”

“What does he want?” John asks quietly, slipping out of the office.

“He wants a retest. You aren’t in your office. Where are you?”

“I’m…” John looks around. “I’m at my flat. Montague Street. I… well… I didn’t feel so well. Thought I’d take a nap and then return at sixteen for my patient.”

“Ah.” John can hear Molly talking to someone else in the room, possibly Lestrade. He shifts from one foot to the other, anxiety gripping his stomach.

“Lestrade’s on his way,” Molly tells him moments later, but John’s already halfway disconnected. He dials Seb next; the call rings out for several tense seconds.

“Pick up, you bastard,” John growls into the receiver.

“What, Seb?” Sebastian drawls suddenly. John looks around before walking to a secluded corridor.

“Lestrade’s on his way over. Get your arse up to the flat. He’s going to test your blood.”


	5. CAG (GLUTAMINE)

Lestrade enters the flat briskly with the screening materials to see Dr Moran sitting in a chair, looking expectant. There’s something different about his face – more aged, more lined, more hardened.

“Sorry for keeping you waiting,” Moran says gruffly, and his voice seems several pitches lower. Lestrade frowns, taking a seat across from Moran and pulling out the syringe and scanner.

“No problem. It won’t take long, Dr Moran,” he reassures.

“It better not,” drawls Moran, leaning back and extending his forearm for the syringe. Lestrade laughs, before sticking the needle into the vein at the crook of Moran’s elbow and pulling back the plunger.

The blood comes easily. Everything checks out.

Lestrade raises an eyebrow at Moran, who frowns.

“What? Who were you expecting?” he demands.

“No one,” Lestrade says quickly. “No one at all.” He stands up, shaking his head. “I better get back to Bart’s. You’ll be back for your appointment?”

“Appointment?” echoes Moran, looking puzzled.

“Yes. Don’t you have one in an hour?”

Moran blinks and nods. “Yes, yes. Um... thank you for reminding me. Slipped my mind.” He beams, but makes no move to escort Lestrade to the door.

Lestrade frowns at Moran, feeling something rather off about the entire situation. Out the corner of his eye he spies the spiral staircase; slowly he moves towards it with every intention to investigate. After all, Moran isn’t acting like himself. The voice is a bit different. His reluctance to move is strange. All of the alarms are going off in Lestrade’s head, but he doesn’t have conclusive proof; he needs to –

His mobile rings. With a groan, Lestrade moves to answer it, stopping as he does so.

“It’s me,” Sherlock says from the other end. “We’ve caught the killer. He’s detained at Bart’s.” He hangs up promptly; Lestrade sighs, eyes Moran suspiciously, and leaves the flat.

Sherlock meets him outside Bart’s, expression grave. “Donovan’s with him,” he says in a voice that speaks volumes about his opinion of her.

Lestrade expects to see Watson, the bespectacled dishwater blond ex-cleaner from the identification pictures. He doesn’t expect to see Mike Stamford sitting in the office that Sherlock leads him to, supervised by Sally Donovan. Stamford’s eyes are downcast; his wrists are cuffed.

“What’s this?” Lestrade asks Sherlock.

“Freak figured it out. Said we were focusing too much on the eyelash and not on the eye. We found Stamford’s saliva in Murray’s eye, sir,” Donovan answers, sending a scathing look at Sherlock. “We also found his prints on the keyboard; they were the most recent layer.”

Lestrade drops into a chair across from Stamford. “Why did you do it?” he asks quietly.

“They were going to cut the teaching programme,” Sherlock cuts in. “Moran told me that Stamford had been with the teaching staff recently. You heard it from Moran. Their teaching programme is unparalleled.”

“Speaking of Moran, there’s something very wrong –”

Sherlock silences him with a finger. “None of my concern,” he snaps. “I verified my theory by finding Stamford's in-Valid brother. Jeff Hope Stamford, Mike’s older brother, is a borrowed ladder.”

“What does that have to do with anything?”

“It has to do with Moriarty. All of the crimes committed recently are either perpetrated by borrowed ladders or people who have contacted borrowed ladders. Moriarty’s on the move, Lestrade. His network is expanding.”

“But that has nothing to do with the murder! I don’t see –”

“You do see, but you don’t _observe_!” Sherlock leans in close, his face taking up Lestrade’s entire field of sight. “It only seems disconnected because Moriarty never has direct contact with his crimes; he must stay above everything. True, borrowed ladders tend to fall out of communication with their Valid family members, but Moriarty, through those transactions, finds potential new clients for his criminal network in those family members. Am I correct?” he adds, turning to Stamford.

Stamford nods.

“Moriarty is what holds these seemingly unrelated crimes together. He is the link between estranged family members, the six degrees of separation between perpetrators and victims. He is a spider at the centre of a web with a thousand rays, and only he knows exactly how each one dances.”

Lestrade frowns at that. “So Watson’s got nothing to do with it?” he asks, trying to get the facts straight. But Sherlock is already restless, already pacing back and forth with his fingers steepled, his brows furrowed.

“Yes, yes, isn’t that obvious?” he snaps. “Watson was never relevant in this case.”

* * *

The instant John steps into the flat at Montague Street he sees Sebastian sitting in a chair, staring across the coffee table at James Moriarty. Moriarty is helping himself to tea and biscuits that he must have procured for himself, because Seb’s wheelchair is nowhere in sight.

“Holmes?” Moriarty asks John as he takes a seat, shifting uncomfortably. “Tea?”

“What?” John asks, wondering if he heard the Forger correctly on the first question.

“Tea, Johnny-boy?”

John wrinkles his nose, but accepts a cup. He sniffs it gingerly.

“Don’t worry your pretty de-gene-erate head. There’s no poison, cross my heart.” Moriarty smirks over the rim of his cup at John, who frowns but sips anyway.

Moriarty turns his attention back to Sebastian, who has folded his legs into something like a natural sitting pose. “You must control poor Johnny-boy here,” he simpers, pulling a rather hurt expression. “He’s got himself… _involved_ with Sherlock Holmes.”

“What – no –!” John says almost automatically, nearly spitting out his tea at that.

“You’ve only met him a couple days ago but you’ve already accompanied him on one of his cases, haven’t you?” Moriarty leans in, black eyes dancing wickedly. “Danger calls to you, doesn’t it? Isn’t it intoxicating? The dangerous aura of Sherlock Holmes. You must be so _smitten_.”

“I’m not –”

“No, of course not,” Moriarty dismisses, waving a hand. “But then again, you showing up to the bank with him this afternoon is a bit dodgy, isn’t it? People might talk.”

John blinks. How the hell does Moriarty know about that?

Sebastian leans forward, eyes wide and knuckles white. “Is this... true?” he asks, directing the answer at both of them. Slowly, John nods. Moriarty grins.

“He’s such a naughty little pet, isn’t he? Always loosening his leash.”

“I’m not a pet!” snarls John. “If anything it’s Hamish who should be the pet; he’s cooped up here –”

“Because he’s giving you his identity so that you can play doctor every day.” Moriarty feigns yawning. “How dull and predictable, Johnny-boy. Let me give you a bit of advice: when someone genetically better than you tells you to do something, you better do it. Seb, or _Hamish_ as you call him, is only looking out for both of you. Do you want to the news to get out that the best surgeon at Bart’s is a fucking de-gene-erate?”

John cringes, shaking his head fervently.

“Then by all means stop associating with Sherlock Holmes!”

John opens his mouth to protest, but Moriarty raises a finger, silencing him.

“He’s a dangerous man, Johnny. One minute he claims he‘s your friend; the next he betrays you.” At that, John wonders if Moriarty is speaking from personal experience with Holmes, but he doesn’t say a word. Moriarty continues, seemingly pleased with John’s silence.

“The people he runs with are dangerous, too, in their own right,” the Forger drawls over his teacup. He sips. “Their most important job is to prevent people like you from ever attaining your dreams.”

His words are relentless. John shrinks away, curls into his chair. He feels insignificant, like a pawn between people more powerful than and genetically superior to him. It tugs at his chest in a rather painful way.

“If you want to preserve everything you’ve worked for, John, then you’ll do this.” Moriarty leans in, almost spitting the next words in John’s face. “Don’t. Associate. With. Sherlock. Holmes.”

John’s lower lip quivers. “All right,” he whispers, but a sinking feeling in his gut tells him that he’s lying.

* * *

Sherlock wonders why John ignores him when he steps into the office. The surgeon is steadily filling out forms without acknowledging Sherlock’s presence, even when the Identifier greets him and asks him about his latest patient.

It hurts. He wonders if this is what some people feel around him.

Sherlock leans over John’s shoulder as the other continues to ignore him, looking at the papers in John’s hand. They’re the results from a couple days ago, the results of Irene Adler’s heart tests. He sighs, remembering seeing a new body in the morgue that morning and Molly Hooper doing the screenings only to find Adler’s name splashed across the screen.

“She’s dead,” he tells John, putting a hand on the other’s shoulder.

John flinches. “Don’t touch me,” he growls. Alarmed, Sherlock removes his hand and steps back, eyes wide.

“What’s wrong?” he asks. John says nothing.

Sherlock pouts. “Answer me, John.”

Still nothing.

“John, please. Talk to me.”

“I’m not John,” John snaps.

“Sebastian, John, Sebastian. Does it matter?” Sherlock rolls his eyes. “Irene Adler is dead. Does that matter?”

“I heard you the first time,” snarls John. “Don’t bother me.”

“He got to you, didn’t he?” Sherlock asks, crossing around the desk to sit across from the surgeon. He tilts his head in amusement. “Moriarty threatened you, urged you to stop contacting me because he doesn’t want to be exposed. He told you that if you talk to me again you’ll lose Moran’s identity.”

“Excellent deduction. Now go away.”

“John, please. I would never give you away.”

John looks up, and for a moment Sherlock is taken aback at the unnatural shininess in the corners of his eyes, at the sadness lining his face.

“How would you know? How can I be sure that you’ll keep your word?”

Sherlock sighs. “And how can you be sure that Moriarty is to be trusted?”

“You know I contacted him to become a borrowed ladder?”

“Who doesn’t, these days?” Sherlock tilts his head to the side. “And Moriarty intends on using you against me, if your reticence is of any indication. He knows about the bank?”

John nods.

“Ah. As I thought. You’re being spied on.”

“Spied on!” John rolls his eyes. “You can’t be serious.”

“Yes. Borrowed ladders who work in the bank. Possibly even Jeff Hope himself.” Sherlock pauses. “The case’s closed, by the way. Dr Murray was killed by his deputy Mike Stamford, as a reaction to Murray’s threats to cut the teaching programme. This means you’re not under suspicion anymore.”

“But Lestrade probably suspects that I’m a borrowed ladder,” John points out, frowning. “He went to test Moran’s blood and... well, Moran’s voice is a bit lower and his personality is... well, um.” John pauses, licking his lips. “I think he might suspect me of being... well, you know.”

Sherlock laughs harshly. “I _said_ , I will try my best not to reveal you. I lied to him for you before. I can do it again.” He pauses. “You’re not the only one with a job on the line at this point.”

John’s laugh is rich and perfect, and Sherlock wishes he could listen to it forever. He reaches out with a smile and deposits traces of himself all over the ridges and lines of the surgeon’s hands.

“Thank you,” John says once he’s laughed himself half-hoarse, and Sherlock can only smile at him and say nothing, because nothing is enough for once.


	6. AAC (ASPARAGINE)

The text breaks the mid-morning moment. John watches Sherlock read the message with a frown. Moments later, the Identifier is a whirlwind of bustle and activity, swinging on his dark coat and blue scarf and winding his way out the door. John is left alone once more, utterly dazed and lost.

It turns up in the evening news. James Moriarty has been caught breaking into the computer systems at Gattaca UK. Sherlock is the chief witness at the trial. The recent Bart’s director case has earned him positive press attention, and his knowledge of Moriarty’s actions qualifies him for a spot on the witness stand. John doubts, however, that the trial will work out smoothly. If Moriarty isn’t up to something, he would have resisted capture. Therefore there must be a plan in his mind somewhere that involves him getting caught and tried, and John suspects he’s involved somehow.

Turns out he’s right.

John takes the day off at the hospital to watch the trial. Sherlock is at the witness stand, all coolness and poise. Moriarty sits in the defendant’s chair, silver handcuffs holding back his arms. He’s chewing a piece of gum and eying the jury threateningly.

John tries to look innocuous, tries to look like any other spectator. Sherlock catches his eye and smiles briefly, and John can’t help but smile back as Moriarty’s barrister begins the cross-examination. But that has its consequences – Moriarty notices, too, and turns to make a face at John.

John’s stomach plummets.

“Have you any proof to back your accusations against my client, Mr Holmes?” the barrister demands.

Sherlock rolls his eyes. “You’re missing the point. Moriarty cannot be proven by anything except his own records, which he obviously would keep hidden and which may already have been destroyed. Only an utter _idiot_ would attempt to catch him red-handed.”

The Identifier pauses, and looks at John again.

“He’s obviously profiting off the belief that the playing field needs to be levelled for in-Valids, using it to his advantage. But it’s not money – because it does bring in a lot of money, doesn’t it? – it’s the power he seeks.”

“You claim to be an Identifier who can deduce the birth status and occupation of possibly everyone in this room. Can you give any proof –?”

“I don’t see how my methods pertain to the case,” Sherlock growls, but his eyes briefly flicker over the jury box nonetheless. He blanches slightly; at that, John looks over, too.

The jurors look absolutely ordinary. John’s not sure at first what Sherlock sees in them. But even as he watches, one of the jurors reaches up to scratch her nose and John can barely make out the shape of a blood sachet under her fingertips.

There are borrowed ladders in the jury. The entire jury is probably made up of borrowed ladders.

Naturally, Moriarty is cleared of all charges.

* * *

_Sherlock Holmes, paranoid and eccentric Identifier with conspiracy theories. There’s nothing wrong with our society. The last borrowed ladder was Vincent Freeman. The in-Valids are in their proper place. Ignorance is bliss._

Sherlock can almost see the headlines, hear the reporters. The instant he saw that the jurors were all borrowed ladders he had realised that he would not win this round. And as soon as Moriarty’s free, he would...

Steps. A creak. Sherlock pours two cups of tea, purposefully twirling Moriarty’s handle to the right. He picks up his violin and starts to play, masking the footsteps up the staircase.

“Most people knock,” he calls out once the footsteps pause. “But then again, you aren’t most people. The kettle’s just boiled.”

“Violin Concerto by Doyle, opus B, no. 221,” tsks Moriarty in response as he enters the sitting room. “He wrote that for twelve fingers. You’re missing two.”

“Modified,” Sherlock replies.

“He’s rolling in his grave.”

Sherlock’s mouth twitches upwards as he turns to face the Forger. He indicates the red armchair with his bow, but Moriarty sits down in the other one. Sherlock grimaces, but makes no comment.

“I’ve a little problem I’m dying to resolve,” Moriarty sighs as Sherlock offers him the cup of tea, and the Identifier smirks in pleasure when he notices Moriarty twirling the cup handle around with a scowl. “This little issue between us... the final problem.”

Sherlock says nothing, only continues to examine Moriarty as if he’s a specimen under a microscope. Moriarty grins at him as he gently blows on his tea and takes a sip.

“I have it on good authority that you’ve taken a fancy to one of my clients?” he asks.

“Authority meaning spies,” Sherlock replies drily as he sits down with his cup as well. “Jeff Hope?”

“Who else? Aside from, you know, the man who was on the phone when you and John barged onto the trading floor. And the woman with the hand cream on her desk.”

“Not actually hand cream,” breathes Sherlock. “Fingerprint disguiser. Hand cream may make her prints more obvious.”

“Just so.” Moriarty smirks. “I’ve been watching you for a long time, Sherlock. Watching you undo so many of my clients’ hard work, ruin so many lives… you and I, we’re just the same. Except you’re on the side of the Valids.”

Sherlock raises an eyebrow as he, too, sips his tea. “You’re not here to discuss that.”

“No, no, I’m not.” Moriarty quirks an eyebrow as well. “You’ve seen what I can do now, with the trial, the jury…”

“Advertising.”

“You helped, tremendously. And by the way, Irene Adler isn’t dead. The database’s been hacked. Clever girl, Irene. She’s gone into hiding.”

“Because I exposed her?”

“Well, hiding’s not exactly the best word for it when you put it that way. No, no, no… she’s gone on. Elsewhere. Travelling the world with the aid of her donor’s DNA. Escaping the strict classist society of London, one that’s been reinforced by genoism.” Moriarty laughs shortly. “Have you told the Yard why I did it?”

“Why you broke into Gattaca UK? No.”

“You do understand, though, am I correct?”

“Obviously.”

Moriarty beams at him, but the smile doesn’t reach his eyes. He waves his hand, as if urging Sherlock to tell him. To prove that he understands.

Sherlock sighs. “It was a demonstration of your skills as a Forger. Not only do you give the donor and the in-Valid the means for said in-Valid to integrate seamlessly into society and avoid all standard measures of security, but you also can provide more risky manoeuvres for infiltrating organisations that have tightened their security in the face of this perceived new threat. You have the key now, the key to changing the shape of society.”

“What a brave new world,” agrees Moriarty. “With a few lines of computer code I can delete the existence of any in-Valid who chooses the path of no return. I can delete the need for evading security screenings altogether. If I’d bothered to use the key on his profile in the database at Bart’s, John Watson wouldn’t have to use Sebastian Moran’s piss every day. He could just use his own and no one would be the wiser, because it’ll show up in the database as Sebastian Moran’s anyway. Humans have been reduced to a code that uses only four letters. It only takes a couple of mutations.”

Sherlock nods. “Yes, that would make the assimilation process for borrowed ladders far easier, wouldn’t it?”

Moriarty chuckles as he takes a sip. “Oh yes. So now the playing field’s levelled. You know no one ever gets to me.”

“I did.”

“You’ve come the closest,” agrees Moriarty. “What with the trial and everything. Now you’re just in my way!”

“Thank you.”

“I didn’t mean that as a compliment.”

“Of course you did.”

Moriarty snorts. “Have it your way.” He shrugs. “But really, it boils down to this – do you know what happens to you if you don’t leave me alone?”

“Oh, now we’re resorting to warnings?” Sherlock grins darkly at Moriarty from the rim of his teacup. “Let me guess … I get killed?”

“Please, don’t be _obvious_.” Moriarty’s eyes trail around the flat. Sherlock follows his gaze, his stomach curling unpleasantly when he sees Moriarty’s gaze land on a long roll of paper. John Watson’s genetic profile. “I’m not going to kill you just yet; that’d be too _boring_. No, Sherlock, if you don’t stop prying into my affairs and outing all of my clients, I will burn you.”

At that, the Forger sets down his teacup, crosses over to the rolled-up analysis, and takes out a lighter. Right in front of Sherlock’s eyes, Moriarty unrolls John Watson’s profile and sets it against the lighter’s flames. Slowly, the paper begins to curl and yellow as the flames rise around it, and Sherlock is pretty sure Moriarty purposefully leaves John’s name and picture as the last ones to burn.

Moriarty blows out the flame after a moment, drops the remnants of the paper, and kicks lightly at the pile of ash as he resumes his seat. “I will _burn_ the _heart_ out of you,” he says calmly, and despite his usually impeccable emotional control Sherlock feels a tingle of fear shoot down his spine. Moriarty’s made his intent clear; it doesn’t take a deductive genius to know what he means by burning John’s profile, of all papers.

“I’ve been reliably informed that I don’t have one,” Sherlock mutters.

“We all know that’s not quite true.” Moriarty winks at him as he resumes sipping his tea. “So if you’d like to keep him safe, you’ll stay away from me. We’ll all fall down together if you don’t – you, me, John Watson.”

Sherlock says nothing once more, eyes downcast as he sips again.

“This is our final problem, Sherlock. Don’t be scared, though – falling is just like flying, except with a more permanent destination. You know the easy way out; I’ve given it to you. But then again, people like you never seek that kind of answer, do they?”

Sherlock nods. “Not at all,” he murmurs, eying the pile of ashes that used to be John Watson’s genetic profile. The fire has burnt most of John’s photograph, but his eyes still remain intact on the charred paper.

Sherlock can’t help but feel a thick sense of foreboding settle into his chest.

* * *

John can’t sleep.

It’s after the trial, after the verdict. Despite Moriarty being acquitted, the police are taking no chances with Sherlock’s warnings. Already on his way home from the courthouse John has had to submit to three spot checks, luckily none of which involved intravenous blood or saliva samples.

Those had been easy to bypass for someone with experience. And Moriarty would bail out the jury if they get caught.

But still, that’s not what keeps him awake.

John sleeps down the hall from his donor. Sebastian’s legs pain him whenever he puts pressure on them, so John always carries him to bed and helps him in and out of the tub when he goes to bathe. It’s all an extension of his duties as a doctor. He doesn’t mind.

But this is different. This isn’t totally about Sebastian’s legs. This is about Sebastian himself.

The man’s been having resurgences in his nightmares.

He’d been invalided home from Afghanistan five years ago, a couple months before they began their arrangement. But John knows Sebastian is still plagued by nightmares of the blood and sand and death he had seen. He may not be haunted by the war – he may even miss it – but the war is all he can dream of, spurred by his quiet discomfort over staying in the basement all day. Cooped up like a caged bird.

“John!” Sebastian calls in the dark, and John is in the Valid’s room in an instant. Moran is sitting up as best as he can, staring at the opposite wall but probably not seeing anything there. John reaches for him, holding him tight and wanting to comfort him the best way he knows how.

“What is it this time?” he asks quietly. “What did you dream about?”

Sebastian never answers that, only holds onto John like a drowning man to a life preserver. John offers to get him something to drink. He demands a glass of whiskey. John finds it in the mini-bar across the room and gives it to him.

“It’s hard being perfect,” Sebastian says after a moment. John would harrumph at that, but the look on his donor’s face is so lost and melancholy that he can’t bring himself to respond in such a way. “You know, I used to hunt tigers.”

“Tigers?”

“Yeah, or at least what’s left of them. Crack shot, I was. But you’ve never seen the trophies. I had them pawned the instant I was back in London. Knew I’d need the money.”

“For gambling,” John remarks, but without any edge in his voice. He, too, had been a bit of a gambler in his early days. Not like he had anything to lose as an in-Valid. Sebastian takes a swig of whiskey and looks at him, cerulean eyes shining pale in the moonlight filtering in from the window, and for a moment John sees the shimmer of tear tracks down the ex-soldier’s face.

“When you’re perfect, what do you live for? And when your perfection gets wasted, what can you do? There’s no gene for fate. I got shot, and that was it. My life as I knew it, over.” Sebastian takes another swig. “It was just the shoulder.”

John pauses. “What?”

“I was only shot in the shoulder. What happened to the legs was my own doing.”

“What do you mean?” John whispers, looking directly into Sebastian’s eyes. The other man looks back as he finishes his drink, but John’s not sure if Moran is actually looking at him.

“It wasn’t an accident, or an injury of war. I walked in front of a Humvee. After I got shot, I walked in front of that damn Humvee.” Sebastian blinks, and grabs John’s shoulders with a wince. “Seb, I… I’m a failure. Couldn’t get out of the war unscathed, couldn’t even get my own death down right. I was born perfect, so why can’t I do a single goddamned thing with my life anymore?”

“Hamish, you need to sleep,” John says, voice weary as he takes the now-empty glass away from his donor. Sebastian laughs darkly, before lying back against the pillows. John looks down at Sebastian’s almost-lifeless legs, sighing. “It’s all right. It’ll be fine. I’ll be here if you need anything.”

“Keep me safe, won’t you?” And Sebastian’s voice is just so goddamned vulnerable as he says that that John is nearly moved to tears. He reaches out, pats the bad shoulder as gently as he can, and nods. It’s a waste of gesture in the semi-dark, but it’s the thought that counts.

“I will, Hamish.” Slowly John gets up and leaves the room with the glass, closing the door behind him.


	7. TGC (CYSTEINE)

Sherlock Holmes has never looked for an easy way out. He’s not about to start now.

“So, what is this exactly?” John asks as they look down at the menu in the dimly-lit high-end Italian restaurant. “Some sort of date?”

“I would say I’m on a case,” Sherlock replies casually, looking out the window. “But then I could be lying. It depends on whether or not the target adheres to his schedule.” A pause. “You don’t mind, do you?”

“Actually, I think I do. But you’re the Identifier; who am I to criticise?”

Sherlock laughs harshly, and opens his menu. “You might as well eat, though.”

“Dunno if I can take the chances,” John mutters. “I just realised I left the salivary substitutes at home.”

“Do you think the police are going to barge in here for a spot check?”

“Possibly.”

“Point conceded.” Sherlock rolls his eyes. “But there’s been no major crime since Moriarty’s, so if anything, the check probably won’t be very thorough.”

“How would you know?” John demands, but Sherlock shrugs and turns back to the window. He watches the cars zoom by on the twilit London street, the lights flashing brightly.

John orders a basket of breadsticks, presumably because he doesn’t want to take too many risks without his salivary substitutes. Sherlock keeps his eyes trained on the street outside, looking for the target, a banker named Eddie Van Coon, another borrowed ladder at Sebastian Wilkes’s bank and possibly one of Moriarty’s spies...

“So. I’m assuming this is a date?” John asks as the breadsticks arrive. He grabs one and tears off a chunk with his teeth, grinning roguishly. “You’re treating me to dinner at an expensive Italian restaurant with a single candle in the middle of the table.”

“Would you like for it to be called that?” Sherlock wonders, sipping his water distractedly. “I mean, it’s really not my area.”

“Do you have anyone who’d be after you for doing this?” John asks. “No girlfriends?”

“Nope. Like I said, not really my area.”

John chuckles lightly; Sherlock looks at him and wonders again what John’s eyes really look like. His smile is so frank, so open – he seems so at ease with Sherlock even though both of them know it’s like watching a minnow become friends with a shark.

Friends? Odd thought, that. Sherlock purses his lips in thought.

“So... do you have a boyfriend, then?” John wonders.  “Which is fine, by the way –”

“I know it’s fine,” Sherlock interrupts. History textbooks tended to play up the integration of all races and sexualities in order to block out the segregation of Valids and in-Valids. Hypocrites, the lot of them.

“So you’ve got a boyfriend.”

“Nope.”

“Oh.” John raises an eyebrow at Sherlock. “So you’re unattached, like me. Fine. Good.”

Sherlock frowns at him, wondering why his own insides are quivering with something akin to excitement. It scares him as much as it thrills him – possibly even more, because he’s never felt anything like this before.

“John, I’d like you to know that I’m more or less married to my work –” Even as he begins to speak, Sherlock notices John starting to shake his head. Did he read the man wrong? Was John –

 “Oh god, no! I wasn’t hitting on you!”

Apparently he did.

John’s cheeks are pink again, and Sherlock reckons that it’d been better when he thought that John _was_ hitting on him. John takes another bite of his breadstick, swallows thickly, and explains, “I was just saying that it’s _all_ fine. You’ve seen my profile. What are the chances of someone like you falling for someone like me?”

Sherlock wants to tell him that it’s a lot higher than he thinks, but at that moment the doors to the restaurant slam open. In steps Anderson, who is wielding a handheld scanner and a bag of swabs. Saliva testing. Sherlock looks at John, who nearly chokes on his third bite of breadstick when he sees the policeman.

 “Evening!” Anderson calls out. “This is just a spot check, no need to panic. Just please don’t vacate the premises.”

Everyone complies, mostly because Anderson’s back-up officers are blocking all possible exit routes. Anderson begins swabbing the mouths of all of the customers, while a deputy officer goes back to test the employees.

* * *

Sally Donovan stops Sebastian as he wheels himself out to freedom for the first time in ages. The last time he had managed to do so was when John first secured himself a spot at Bart’s. He’s long overdue for a night out.

He’s only halfway down the street to the nearest pub when she stops him and has him take a thumbprint scan. Naturally it checks out, but the incredulous look on her face rubs Sebastian the wrong way.

“You’re Sebastian Moran?” she asks, frowning.

“Well, of course I’m Sebastian Moran!” Sebastian snaps. “Who’d you think I was?”

Sally bristles at his rude tone. “It doesn’t say in the database that you’re crippled,” she points out bluntly.

“Yeah, well, I had a nasty incident with the stairs today. Sprained my ankle pretty badly, but it should be functional tomorrow morning. Who the hell do you think I am, to stop me like this and demand my genetic profile? Look at me!”

Sally glares, turns about, and starts heading away, but Sebastian wheels himself in front of her.

“Look at me!” he growls. “I have a genetic quotient second to none. Probably even better than yours. Is this how you treat your betters? Fucking look at me, flatfoot!”

Sally refuses to comply, only sidestepping him on her way down the road. Sebastian tries to intercept, but after a moment he falls behind and resorts to yelling after her.

“I could get you for harassment, you know! What’s your number?”

Sally vanishes into the night, head held high and expression stiff.

* * *

When Anderson gets to Sherlock and John’s table, John sends Sherlock a pleading look before stopping Anderson in his tracks.

“I’m so sorry, but I don’t think you should swab my mouth,” he tells Anderson.

“Oh, it’s you,” Anderson groans, but he’s looking at Sherlock, not John. “How’d you get a date? Did he follow you home?”

“Yeah, that’s kind of the point,” John cuts in. “You’re going to get a contaminated sample if you swab us. Sorry.”

Sherlock shoots him an amused glance, and then smirks at Anderson.

“Your wife out of town again?” he asks. “You stink of cheap in-Valid perfume.”

Anderson colours brightly and splutters, before holding out the scanner. “Just... press your thumbs,” he growls. John and Sherlock comply and check out, and the red-faced Anderson quickly moves onto the next table. Sherlock turns to John again, amusement etched all over his features.

“Contaminated sample?” he whispers.

“You don’t know where those swabs have been,” John replies innocently as he finishes the breadstick.

They leave the restaurant soon after that, Sherlock having decided that the borrowed ladder would not venture out when the police are making their rounds. It’s a long shot, but then again the real excuse for the dinner had been to thumb his nose at Moriarty. And to spend some time with John.

They head back to 221B Baker Street, but instead of entering the flat Sherlock leads John around to the back and climbs up the fire escape. John follows suit; they emerge onto the roof, where the night sky stretches before them, sprinkled with stars.

“It’s lovely,” John remarks.

“Dull,” Sherlock replies. “Beautiful for the moment, but otherwise not worth remembering.”

“Not worth remembering?” echoes John, turning to face Sherlock. Sherlock shrugs and pulls his scarf and coat closer to him.

“I prefer to remember other things about tonight,” he replies.

They sit side-by-side in companionable silence. Sherlock’s not sure who started it first, but soon John’s arm is at his waist and his arm is around John’s shoulders, and the in-Valid is leaning in close, head almost resting against Sherlock’s shoulders but not quite. Just hovering, and that’s somehow way too far.

This is nice. Just sitting here, looking out at London, letting John’s ordinary, placid mind balance out the chaos in his. John is nice. It’s as if the past few years of building his reputation as the most accurate and merciless Identifier in London (and possibly the world) don’t count, because the instant John Watson stepped into his life he had turned it upside-down. With one little lie, Sherlock finds his entire world crumbling at the edges.

Why John? Why him? Why now? And why, oh _why_ does it have to be so bloody _complicated_?

“You’re thinking,” John says suddenly. “I didn’t know this situation calls for _thinking_.”

 “I can’t turn it on and off like a tap,” Sherlock retorts immediately, but the smile on John’s face softens his own expression. “Sorry.”

They stay out all night, watching the stars fade away and the sky lighten from black to purple to indigo. Then the sun begins to rise, glittering off the surfaces of solar panels and the sides of tall office buildings. John occasionally nods off against Sherlock’s shoulder, but he’s definitely awake again to see the sunrise, and as the rosy hues peek over the London skyline Sherlock notices that John’s face is turned up to his and that their lips are dangerously close.

It’d be so easy to just close that distance between them, but Sherlock doesn’t. It’d be so easy to wrap John in his arms and snog him senseless against the concrete, but Sherlock doesn’t.

“We should see a concert tonight,” he says instead. “Violet Smith’s in town. Deadly good pianist.”

“Bit soon for a second date?” John asks, voice thick with sleep but amused nonetheless. “Besides, my donor’d get suspicious. You know Moriarty’s warning.”

Sherlock winces slightly, remembering the remnants of the burnt photograph. He’d kept that piece, next to the correspondence he had knifed to the mantelpiece. Moriarty’s words still haunt him in the quiet hours of the night, when his other thoughts are so distracted that they become only white noise.

_I will burn the heart out of you._

“He won’t,” Sherlock mutters. “I won’t let him do it.”

John’s expression is puzzled, but Sherlock doesn’t bother elucidating as he removes his arm from around John’s shoulder.

* * *

“You’re him. Sherlock Holmes.”

Sherlock looks up from his microscope. A female reporter stands next to him in the lab, eyes wide with excitement as her fingers play with the blue scarf wound around her neck.

“I’m not sure who else I can be,” Sherlock replies drily.

“I’m a big fan of yours. Sign my scarf, won’t you?”

Sherlock raises an eyebrow. “How can you possibly be my fan when the only press attention I have ever received is about that hospital director case?”

“Well, I’d love to know your thoughts about it. How exactly could Moriarty have gotten away with that?”

Sherlock looks her up and down, noticing the ink stains all over her hands and the traces of newsprint about her wrists. She smells of newsprint and coffee. Reporter, possibly investigative, judging by the way she tries to appeal to her subject in order to establish rapport and gain confidential sources. _Bona fide_ Valid.

“None of your business,” Sherlock snaps, looking away from her.

“What’d you find out about me?” she asks quietly, voice already starting to grate on his nerves.

“That you’re an investigative reporter in search of a good scoop, and that you think getting me on the record about Moriarty will do just that. Is it going to be the truth about me and how I work? I don’t respond well to journalists. Good day.”

She wavers, obviously torn between wanting to stay behind and harass him further and leaving him to his devices so he won’t need to call security on her. Self-preservation wins out, though, and she begins to leave. “You’ll need allies, though!” she calls over her shoulder at the door. “You’ll need someone on your side when no one else will be. And I can do just that.”

Sherlock notices her card under the Petri dish once she’s gone; she must’ve slipped it under before she spoke up. _Kitty Riley_ , the card says. _Investigative journalist_. He harrumphs, and pockets the card as the clicks of her heels on the linoleum fade into the distance and the sturdier footsteps of John Watson take their place.

“Your paranoia’s seeped into the rest of Bart’s,” John remarks as soon as he enters the room. “Posters on how to identify borrowed ladders are up and Molly’s anticipating doing another intravenous sample sometime this week. I may have to get something for my elbow veins; I can’t bend needles and switch phials forever.”

“I’m not paranoid,” scoffs Sherlock. “I don’t care about the fates of borrowed ladders.”

John pauses, causing Sherlock to look up and frown. “Not good?” he asks.

“Definitely not,” John snaps. “I mean, even though I don’t need verbal confirmation that you don’t care because you prove it every day, it still stings a bit to hear it.”

Sherlock slumps slightly. “No, wait. Let me explain –”

“What is there to explain? You don’t care about us, which is why you keep turning us in!”

“No! If Moriarty hadn’t decided to make a power play using borrowed ladders, then I would be concentrating my intellect on solving crimes, not identifying de-gene-erates!”

“Oh, so it’s now his fault you’re a sociopath?”

Sherlock clamps his mouth shut and crosses his arms. He deliberately turns away from John, refusing to make eye contact when the in-Valid turns him around.

“Holmes, you are five,” groans John. “I didn’t mean to lash out at you like that.”

Sherlock snorts.

“Look, I’m sorry.” John kneels down next to him and looks up into his eyes. “I’m under a lot of stress. It’s not easy being a borrowed ladder, so when I hear...”

“I mean it, though,” Sherlock cuts in. “I don’t care about borrowed ladders.”

“Or other Valids, either,” John mutters.

Sherlock snorts. “I just care about one,” he continues. “The others are merely links, factors in the web that leads to Moriarty.”

John frowns as if in protest, but he still takes the Identifier’s hand tentatively, remembering Moriarty’s words to him.

_Don’t associate with Sherlock Holmes._

Sherlock nods as well. “So, I assume we are still open for the concert tonight?”

John smiles at him, eyes crinkling. “Definitely,” he says.

* * *

Sebastian wheels himself out of the storage room as John descends the spiral staircase, adjusting his tie and cuffs. “Going out again?” the Valid asks. “You were away all last night. You need to sleep once in a while, you know.”

“And you could stop drinking once in a while, too,” John replies, pointing to Sebastian’s whiskey glass. “Sometimes there’s more whiskey in your piss than there is piss.”

“It’s not like you’re working at Gattaca UK,” sniffs Sebastian.

“Sobriety is also appreciated at Bart’s.”

Sebastian sighs, and sets down the glass to light himself a cigarette. “Be that way,” he scoffs, taking a drag.

“What’d I tell you about cigarettes?” John groans. “They’re bad for breathing, you know that.”

“Breathing’s boring,” scoffs Sebastian. “Besides, you’re missing the point. Are you or are you not going out tonight?”

“Yes. Concert, to see Violet Smith.”

“Who’re you going with?”

John shrugs, looking away. “Molly Hooper.”

Sebastian’s face twists. “Don’t lie to me, Seb,” he growls.

 John sighs at that, tosses his hands into the air. “Fine,” he snaps. “Sherlock Holmes.” He closes his eyes, bracing himself for Sebastian’s anger.

It doesn’t come. John opens his eyes, frowning. Sebastian is slumped in his wheelchair, head bowed and hands clasped as if in prayer. John frowns, moving closer, reaching out. Sebastian shrugs away his comforting hand, turns away from him, and rolls over to a table covered in chemical equipment.

“Go have fun,” he says.

“What?” John asks. “You’re not...”

“It doesn’t matter anymore,” Sebastian mutters, looking back at John with forlorn eyes. “I can’t stop you from falling.”

“I’m not falling in love with –”

Sebastian shakes his head and rubs his temples. “No, that’s not what I – never mind, Seb. I... never mind.”

“How did you get upstairs the other day?” John asks, in a stab to change the subject.

“Oh, I could always walk,” Sebastian intones drily, chuckling. “I’ve just been faking it all this time.”

John laughs, looking at his donor with undisguised fondness. “You are one of my greatest friends, do you know that? You brought me to where I am now. I’m forever in your debt.”

At that, the smile slips from Sebastian’s face. “I love you, John,” he says with all seriousness, “as my best friend. Keep that in mind later on.”

“Of course,” John replies.

“No, you don’t understand. I got the better end of the deal, didn’t I?” Sebastian smiles up at John, but there is melancholy beneath those cerulean eyes once more. John wonders what’s plaguing his donor, and he raises a quizzical eyebrow, urging Sebastian to continue.

With a sigh, the Valid does so. “I only lent you my body. You lent me your dream.”

John stoops down and enfolds Sebastian in a hug, trying his best to shove away the rising lump in his throat, to dry out the excess moisture in his eyes. When they part, John smiles at Sebastian, pats his shoulder, and steps away.

“Don’t wait up,” he says weakly, smiling through the tears that threaten to blur his vision.

“I won’t,” Sebastian replies, as John turns and leaves the basement.


	8. CCC (PROLINE)

Violet Smith is a world-famous pianist with twelve fingers. She’d been designed by her parents to be a musician, and then trained with the best twelve-finger music teachers. Tonight her concert will comprise of several solos and four duets with a renowned twelve-fingered violinist by the name of Shan.

John’s painfully aware of how close Sherlock’s fingers are to his all throughout the first couple of solos. As the pianist’s fingers fly across the keys, his own fingers itch to entwine themselves with Sherlock’s, to imprint Sherlock’s DNA onto his skin. Sherlock looks at him sidelong, smiling knowingly. John blushes and ducks his head.

They only make it to intermission. As soon as the lights go up for intermission, the police march in. But this time, it’s not for a spot check.

“Sherlock Holmes! Can anyone tell us where Sherlock Holmes is sitting?” the voice of DI Lestrade calls over the din of people getting to their feet and exiting the hall, and John stands up to see Lestrade heading down the aisle towards them.

“Do you know what he wants?” he asks Sherlock, who shrugs. Lestrade is consulting an usher now, showing him a badge and several papers. It doesn’t look good. John tugs Sherlock from his spot and the two of them leave with a group of other concertgoers, heading for the reception.

“Freak!” someone cries, and John turns to see yet another police officer head for them. “Stop right there! You’re under arrest!”

“Oh god, it’s Donovan,” Sherlock growls, pulling at John’s sleeve. “Come on, take my hand.”

“Stop!” cries Donovan, but she is still too far away; they’re separated by a queue for the loo. Sherlock and John take one look back at her and take off for the doors to the concert hall, hand in hand.

A security guard attempts to stop them, but John punches him out of the way and drags Sherlock out of the hall and through the elaborate gardens at the front of the building. They reach the main road and take off in a random direction; after a couple of streets they can hear the sirens in pursuit.

A giant chain-link fence suddenly obstructs their pathway. Sherlock moves to scan their way through, but John pushes his hand away and starts removing the adhesive around one of his fake fingerprints. “Databases track us, remember? They know Sherlock Holmes is on the run with Sebastian Moran. They’ll know you’re in the in-Valid quarter if you scan in.”

Sherlock steps back as John scans into the in-Valid quarter as John Watson for the first time in years. The fence swings open for him; he pulls Sherlock through and they run down the ill-paved road past the gloomy tenement-style houses.

“I hate this place,” Sherlock grumbles as they continue to run, and John can’t reply because his heart is pounding and his knees feel like they’ve turned into water. After a moment, he drags Sherlock to a stop in the shadow of a forlorn brick building, panting heavily.

“You hate it, yet you wish it on other people,” he gasps, leaning against the wall as he attempts to reattach the fake thumbprint. “We can’t hitch a ride on the trolley that takes in-Valids out through the main gate; they’ll be scanning that and you’ll turn up in the database. What if we...”

A police car zooms by, lights flashing. Sherlock pulls John deeper into shadow, pressing their bodies together in the narrow alcove. All thoughts of escape melt in John’s mind as he realises just how close Sherlock is to him, how scandalous their situation may look to unsuspecting passerby. And somehow, he doesn’t mind.

“A plan,” Sherlock mutters, rubbing his hands. “We need a plan...”

He looks up. John follows his gaze. There is a fire escape leading to the rooftop, and most rooftops are within jumping distances of each other. Aside from that, he’s not sure what Sherlock has in mind.

“The rooftops at the junction between Lauriston Gardens and the main road are close. In-Valid quarters end at the main road. Back alleys aren’t too hard to scale –”

“The skip,” John says suddenly. “The skip over there is unfenced ground, separated only by the gulley and the old train tracks. We can cross under the bridge to avoid detection and use the cleaners’ trolley tracks to get out of there to the back door of Bart’s. Some homeless in-Valids live there, though, so I’m not sure if it’ll be safe for you –”

He’s cut off by Sherlock grabbing the sides of his head. “Brilliant!” the Identifier gasps. “You are brilliant! You are amazing! Yours may not be the brightest of minds but as a conductor of light you are unparalleled!” And with that, he closes the distance, smashing their lips together, bumping their noses together, pressing their bodies together even harder against the alcove. John’s eyes fly open in shock at first, but then they slowly flutter closed.

It takes him an enormous amount of effort to pull away from Sherlock, intoxicating Sherlock, and remind him that they need to get going before the police put two and two together.

So they make for the skip. All around them the police sirens are roaring but it seems that they’ve managed to slip under the radar with John’s fingerprint. Together they run through the overflowing rubbish and down the hillside into the gulley, skipping across the small streams of sewage-dirty water and rusted-over train tracks to the bridge up ahead, where several police cars are parked.

The sounds of police cars fade after a moment, and John can barely make out the lumps of homeless in-Valids sleeping rough under the bridge. No one pays them any heed as they run through their ranks, between the bridge supports, and up to the newer but no less dirty trolley tracks intended to carry the in-Valid cleaners in their trolleys into the Valid world.

The plan goes smoothly up until they reach the back end of Bart’s, and then Sherlock notices a discarded newspaper in the bin outside the cleaners’ entrance.

“The Truth about Sherlock Holmes,” he murmurs, bending down to pick up the paper. “A new exposé by Kitty Riley, using a first-time source... named Richard Brook.”

“Richard Brook?” echoes John, peering over Sherlock’s shoulder at the article. Sherlock takes out Kitty Riley’s card from his pocket and examines it.

“I need answers,” he mutters, before tugging John away.

* * *

The lights go on in Kitty Riley’s flat. The journalist does a double-take at the two figures sitting on her couch. Sherlock looks up at her coolly, cocking an eyebrow.

“Too late to go on the record?” he asks.

“I gave you your chance,” Kitty replies calmly as she closes the door. “I wanted to be on your side.”

“And now someone else is giving you the dirt on me, how well-timed. Who is this Rich Brook and what are his credentials?”

But he doesn’t need Kitty’s explanation. The door to the flat swings open again and in steps James Moriarty, hair tussled and clothes rumpled. He mutters something about not being able to get the milk, but does a double-take at Sherlock and John.

And to Sherlock’s surprise, he backs away.

“You said I was safe here. You said they wouldn’t find me,” he gasps, pointing to Sherlock and directing the accusation at Kitty.

“They’re not going to hurt you, Richard. Not in front of witnesses like me.”

“What the hell is going on?” John asks, frowning. “Why’s Moriarty – oh. I see. You’re Richard Brook, aren’t you? You’re the source.”

“He’s always been Richard Brook,” Kitty replies. “There is a James Moriarty, but he is a paraplegic and a former maths professor. The James Moriarty you know is a borrowed ladder.”

John blinks. “But... no! You are James Moriarty! You threatened me, you threatened Sherlock, you...”

“I’m sorry, so sorry!” Moriarty – Brook – exclaims, palms out in an appeasing gesture. “He paid me to do it!” He points at Sherlock, and John whirls around to look at Sherlock.

“You... wait, what?”

Sherlock can see the doubt and confusion etched all over John’s features. He looks at Moriarty, noticing the glare of contacts in his eyes. Moriarty-as-Brook has green eyes and stubble; he rubs at his face and leers at Sherlock from between his fingers.

Sherlock raises an eyebrow. A borrowed ladder, indeed. But Moriarty is doing it in reverse now. He’s masquerading as an in-Valid.

Ooh, _clever_. Very clever. And the flicker of smug triumph on Moriarty’s face is all the response Sherlock needs.

John rubs his temples. “Sherlock, care to explain? I’m not sure what to believe anymore, what with all of this...”

“I’ll do the explaining,” Kitty cuts in, bringing over file and opening it to show a C.V. and several other documents with Brook’s credentials on them. “James Moriarty as a Forger is the creation of Sherlock Holmes. He paid an in-Valid actor to become a borrowed ladder for this masquerade. Holmes planned and provided for all of the arrangements, and paid for Brook to take the credit so he can slowly dismantle the network and establish himself as an Identifier.”

John scoffs. “That’s ridiculous.”

“It’s the truth,” blusters Moriarty. “It was all paid and provided for by Sherlock and – get away from me!” He directs that at Sherlock, who has taken a step towards him. “Don’t you dare lay a finger on me!”

“Stop this! Right now!” Sherlock shouts, because all he can see is red and the flickers of – was that doubt? – in John’s eyes – he can’t let Moriarty drive this wedge between them; he can’t let Moriarty bury this nugget of doubt in John’s head. No. He can’t lose John, not anymore.

Moriarty flees up the stairs and slams the door shut. When Sherlock finally bursts in after him the windows are open and the curtain is fluttering in the breeze. Moriarty is gone.

Sherlock stops on the upstairs landing, staring at the fluttering windows. The fall. His fall.

“Oh god,” he mutters to himself as he descends the staircase again, brushing past John and bumping a bit harder than necessary into Kitty on his way out. She’s saying something about his regrets over not getting her on his side before it was too late, but he doesn’t hear her. All he hears is the need to get to Bart’s, to see Molly Hooper. To prepare.

That’s why the police had been after him. Moriarty must have slipped them a heads-up about him lying for John. It’s Moriarty’s move now; he’s sowing doubt into the minds of everyone around Sherlock. Preparing them for the lie.

A lie that’s preferable to truth – the lie that he, the great Identifier, is just an ordinary man after all. But there’s one thing left to complete the tale, and Sherlock now realises what it is.

“Are you all right, Sherlock?” John calls after him as they emerge from the block of flats. “Sherlock, wait –”

“No. I have to go to Bart’s. Meet me there if you’d like, in ten minutes.” And with that Sherlock is running away, fleeing from John before he can see the judgement in the other man’s eyes.


	9. CTG (LEUCINE)

A sleek black car pulls up to John even as the sounds of Sherlock’s footsteps fade into the darkness. Out comes a young woman whose eyes are trained on the screen of her phone.

“Get into the car, Dr Moran,” she suggests. “Or should I say, _Mr Watson_?”

John flinches, but he complies. The woman closes the door and moves around to the front seat. Across from John, his face enshrouded in darkness, sits an older man with a portly figure and an umbrella.

“Who are you?” John asks.

“Someone not to be trifled with,” replies the man as the car pulls away from the kerb. “I’d like to ask the same for you. What is your connection to Sherlock Holmes?”

“I... well... he, uh, lied for me. Not sure how that makes me special, but...”

“Indeed.” The man’s face moves out of the shadows. His hair is tufty; his hairline is receding slightly. But his eyes are sharp and young, and his features aristocratic. Almost like Sherlock’s. “You don’t seem very afraid.”

“You don’t seem very frightening,” John bluffs. The man is actually quite alarming, but he doesn’t want to give him the satisfaction of knowing that.

“I’ve been watching you for quite some time,” the man continues carelessly. “Hoodwinking all of Bart’s like that. You fake your identity to save other peoples’ lives. What for?”

John opens his mouth to answer, but the man raises a finger.

“No, no, I understand. The thrill of service and of danger. No wonder my brother likes you so much.”

“You’re… Sherlock’s brother,” John states.

The man laughs. “Mycroft Holmes.”

John relaxes only slightly. Sherlock’s brother or not, the man is still a force to be reckoned with. That much is obvious.

“Well, you must know about Sherlock’s current situation,” he says suddenly. “He’s being framed.”

“Much like your situation when the Yard suspected you for killing Dr Murray, no?” Mycroft asks, grinning. The smile slips quickly, though. “Unfortunately there is nothing we can do to ease Sherlock’s case.”

“What do you mean? We could take an intravenous blood sample from Moriarty and prove –”

“Proves nothing,” Mycroft interrupts. “He has a code. A key that can change the face of society. He used it to break into the genomic database, to turn himself into Richard Brook.”

“So there’s no way to bring Moriarty back?”

“As far as we can see, no.”

John looks down at his hands. “Oh,” he says after a moment. “Well, there’s a huge hole in the story, in any case. If Sherlock planned all of the borrowed ladders, then why’d he lie for me? There’s nothing special about me or what I do.”

“I wouldn’t say that so quickly if I were you,” Mycroft replies, examining his umbrella with a sigh. “But then you’d have to ask Sherlock himself. I’m inclined to believe it’s because you aren’t forwarding your own interests by sneaking into Bart’s, but it could be something else entirely.”

“Why would you say that?” John wonders.

Mycroft smiles. “My brother has the genes to become whatever he wanted. Yet he chooses to do this. He doesn’t choose lightly, you know.”

At that moment, the car pulls up to the front of St. Bart’s hospital. “Here we are,” Mycroft says cheerily, opening the door for John. “He’ll be in the lab.”

John mutters his thanks as he clambers out of the car and rushes into the hospital, checking out through the thumb scanner without any incident. He gets to Sherlock’s lab in time to see Molly Hooper leave; the saddened look she sends to John is enough to stop him in his tracks.

“What’s wrong?” he asks her.

Molly shakes her head. John brushes past her on his way into the lab to see Sherlock sitting there, in front of a microscope but not looking into it.

“You came,” Sherlock says quietly, looking up at him as he clambers to his feet. “You came back.”

“Why wouldn’t I?” John asks, crossing over to him. “Does it matter, the differences between us?”

Sherlock’s lips curve up; they’re so close to John’s. Almost unconsciously, he licks his lips and sets Sherlock’s hand on his chest.

“We share this in common,” he says quietly. “But mine is a thousand beats overdue. I don’t have twenty or thirty years left in here. Does that matter?”

Sherlock says nothing, only stands still and listens, his palm feeling the erratic beating of John’s heart. John looks up at him, vision blurring with tears.

“Does it matter, Sherlock? Answer me.”

Sherlock shakes his head, slowly, like someone learning the concept for the first time. “No,” he agrees. “No, it doesn’t. You’re here with me. That’s what matters.”

John sighs, letting his shoulders slump as he reaches out and pulls Sherlock close to him, breathing deeply against the shell of Sherlock’s ear in an attempt to calm down his racing heart.

“I need you more than anything,” he whispers into the Identifier’s ear, and he can hear Sherlock’s own breath catch in his throat. The next thing he knows Sherlock is kissing him again, pressing him against the counter with his fingers threading through John’s hair. Hungrily and desperately John kisses back, and wraps the other close with a sigh.

For this moment in time it’s only them, and that’s what matters – Sherlock with his rough yet sweet kisses and his skilled fingers, Sherlock with his eyes darkened with lust as he pulls back to look at John through half-hooded eyes, Sherlock with his intoxicating voice, growling against John’s ear as John presses sloppy wet kisses along his jawline, removing the scarf to kiss the Identifier’s exposed neck.

Sherlock’s breath grows ragged. “John,” he gasps, voice tweaking into a moan as John nips lightly at his pale skin.

“Mm?” John wonders, tongue darting out to lick at bitten skin. He leans back, looking into Sherlock’s eyes. “What is it?”

Sherlock makes a needy noise in the back of his throat, something that sends an alarming jolt of warmth to John’s groin. “Don’t stop,” the Identifier warns after a moment, and John complies, fingers undoing Sherlock’s coat as he recaptures Sherlock’s lips with his own.

“I won’t,” he gasps, nudging one leg between Sherlock’s thighs and deftly undoing the top buttons of Sherlock’s aubergine shirt. As he exposes more pale skin with his fingers, his lips and tongue are quick to follow until the shirt is untucked and the last buttons are undone. Sherlock gasps into the empty lab as John kisses a line from his navel to his belt, fingers moving to undo those as well. His long, slender fingers curl themselves into John’s hair, grabbing at the roots. John prays that Sherlock won’t pull. They’ll be leaving enough incriminating evidence as is.

In this moment, they have all the time in the world. It doesn’t matter that it’s just past midnight, or that neither of them has had a decent night’s sleep, or that they were just on the run from the law and Moriarty is out there somewhere seeking their downfall. They’re here, they’re together. No time like the present.

He flips their positions. Sherlock’s shirt is only half-on at this point and John is kissing his lips hard enough to bruise, their breaths mixing in the spaces of their mouths. Sherlock’s tongue slips into John’s mouth; John sucks gently, eliciting a moan from the Valid as he does so. One hand slips down to grasp Sherlock by the hips; as they break apart John only has time to gasp in a breath before he’s back to kissing Sherlock all over, leaving sloppy deposits of himself, of John Hamish Watson, all over Sherlock. Even if it’s only for this brief moment, Sherlock is his.

Once more he sets his mouth onto Sherlock’s chest, nipping, biting, licking, kissing intricate patterns all across the smooth pale skin. Sherlock groans and arches his body towards him, eyes closed and mouth open. John acquiesces to the demand, his tongue flicking at Sherlock’s nipples, hardened against the chilly hospital air. The Identifier mewls, tugging lightly at John’s hair and guiding John’s lips back up to his.

But their kiss is interrupted by the ringing of both of their mobiles. John groans in disappointment; the moment shatters. He pulls his mobile out of his trouser pocket and coughs lightly before answering it, while Sherlock moves away from him to pick up _his_ mobile and read the text message.

“Sebastian, come home,” comes the voice of John’s donor. “Please. I need you.” There’s a choked sob on the other end, causing John to stiffen in alarm.

“Hamish?” he whispers. “Hamish, what’s wrong?”

“I... just come, please. I need to talk to you.”

John looks up, over at Sherlock who is staring at his mobile as if trying to deduce it. Sherlock’s eyes flicker to him; he shrugs.

“I’ll be there in a moment, okay?” John reassures Sebastian. “Just hold on. The concert’s just finished and I’ll be home in a sec. Don’t worry.”

“Quickly,” Sebastian insists, and John hangs up and looks at Sherlock forlornly.

“Your donor needs you,” Sherlock states, stowing his mobile away with a sigh.

“Yeah. Are you all right? What was yours about?”

“Just a text,” Sherlock replies, shrugging. “Go see your donor.” And with that, he turns his back on John. John feels disappointment bubbling in his stomach at not being able to resume what they were doing earlier. The tension between them has soured into awkwardness.

He kisses Sherlock gently, chastely, before leaving the room. He doesn’t notice the sudden set of Sherlock’s jaw or the clenching of his fists. He definitely doesn’t see the contents of the text.

He will, though, soon enough.

* * *

After John leaves the lab, Sherlock looks back down at the text he had received.

_Your move, love.  
Jim Moriarty XOXO_

He quickly types the response.

_Rooftop at Bart’s. Come and play.  
SH_

It is a play off the text Moriarty had sent him when he broke into Gattaca UK. _Gattaca UK. Come and play._ Between the two of them, it is just a game.

Sherlock meets Moriarty on the rooftop, after notifying Molly that he is heading up. The Forger is waiting in the pre-dawn light, sitting on the ledge at the edge of the rooftop.

“Dear me, Mr Holmes, dear me,” he drawls as soon as Sherlock emerges from the stairwell. “You seem to have a much closer relationship with Mr Watson than I’d thought. Oh well, that only makes this so much better.”

“Richard Brook,” Sherlock sighs. “Truly an in-Valid actor who’s donating his DNA to you. You’re trading _down_ , pretending to be an in-Valid.”

“Indeed. And here we are at last with our final problem, and it looks as if I might win this round. How dull is that? I sometimes really hate it when I beat people, especially people like you. Sherlock Holmes, the so-called great Identifier. Now you’re just an ordinary man.” Moriarty yawns and smirks at Sherlock. “Did I get ya? Did you believe me for a moment?”

“You missed the spot about Watson. Did you ever come up with a reason for why I lied about him?”

“Does it matter? I told Anderson about him. He told Lestrade. Funny how some people at Scotland Yard are so desperate to see doubt on your name. You’re so wonderfully charismatic.”

“And therein lies every difference between you and me,” Sherlock deadpans.

“Ah, yes,” sighs Moriarty. “Flip sides of the same coin. I create borrowed ladders. You destroy them. Did you find out about the code yet?”

Sherlock thinks back to Moriarty’s visit, to the bits and pieces of paper left behind after John Watson’s genetic profile had been destroyed. Using four fingers for the four letters, he begins to tap.

“Yes, yes, excellent.” Moriarty grins, eyes flickering down to Sherlock’s fingers. “G, A, T, C, in that order. Gattaca.”

“CODON, the newly developed computer programming language. Each program begins with ATG for Methionine and ends with TAA, TAG, or TGA for the stop codons,” Sherlock declares, grinning. “Instead of amino acids, each codon represents a different command. Your key is just a few lines of code that can break into any genomic database like a virus, a prophage.” He looks back at Moriarty. “Now that I have this code, I can destroy Richard Brook and bring back James Moriarty. You may have changed the records, but now I’ll be able to change them back.”

Much to his consternation, Moriarty throws his head back and starts to laugh.

“Oh god, oh god! Look at you go! I hate to use your words against you, but you’re _wrong_!”

Sherlock stops mid-thought and gapes at Moriarty. Wrong? But how –

“Wrong, wrong, wrong! Sherlock Holmes is _wrong_!” Moriarty cackles with glee, before leaning in dangerously close to Sherlock’s face, spitting the next words at him. “ _There is no key, DOOFUS_!”

Sherlock blinks owlishly at the Forger, who backs away, giggling. Slowly, Sherlock reaches up and wipes away the spit.

“I knew you’d fall for that kind of stuff; you love being so damn logical about things! But guess what? I just did it the old-fashioned way! Asked a nice record-keeper to change my profile, to delete James Moriarty and assign me Richard Brook. If Vincent Freeman can do it, so can I, can’t I?”

“You mean to say you’ve just thrown away your life as a Valid to beat me?” Sherlock asks quietly.

“What does it matter? You were my greatest distraction. And once you complete the final act, it’ll all be over.”

* * *

Sebastian Moran is sitting in his wheelchair by the upstairs window when John arrives back at Montague Street. For a moment John is confused, but then he sees the glistening tear tracks down the ex-soldier’s face and the card held in his hands.

Wordlessly Sebastian holds out the card for John to read, and John’s heart plummets as he does.

_Thank you for doing business with me.  
Jim Moriarty XOXO_

“What has he done?” John demands, taking Moran’s hands and peering anxiously into his eyes. “What did he do to you?”

“It’s... it’s all your fault, John. You chose to associate with him,” Sebastian growls, and the accusatory tone in his voice sends John reeling for a moment before he recovers and sighs. Anger long overdue, it seems.

“Are we talking about Moriarty or Sherlock?” he asks after a moment, leaning against the glass.

“Does it bloody matter?” Sebastian groans. “You associate with one, you bring in the other. But still, it doesn’t matter in the end. He’s dying.”

“What?” demands John. “Who’s dying?”

“Who do you think?” Sebastian snaps. “I warned you; I told you not to! And now he’s going to die and we’ll be ruined.”

“What are you on about?” John rubs his temples and heads for the door, with every intent to return to Bart’s.

“Don’t be so thick-headed.” Sebastian turns away again as soon as John reaches the door. “You know who I’m talking about. Sherlock’s dying.”

John takes a step back, suddenly breathless. “He’s... how?”

“You heard about Richard Brook,” Sebastian murmurs, wheeling himself to John’s side. The card flutters to the ground behind them. “If Sherlock doesn’t fall to complete the story, you will. You and I will go down together.”

From the folds of his blazer the ex-soldier produces a sight. He wheels himself away from John, to the coffee table where the accompanying rifle sits, ready for action. John looks at the weapon, all of the blood draining from his face.

“Moriarty arranged this,” John breathes, and Sebastian looks up at him with forlorn but resigned eyes. “What did he promise in return for my life, Hamish? What?”

Sebastian makes no reply.

“What did he tell you? Answer me!” John snarls, crossing over to the coffee table. But Sebastian seizes the weapon before he can and aims it at John, chest heaving. John backs away, hands raised. “Hamish, what...”

“Sherlock has to fall, John,” Sebastian breathes. “Sherlock has to fall, or else I’m to shoot you – and if I don’t do that, then he’ll expose all of us. He’ll destroy your dreams, John, and I’d... I’d much rather have you dead than to see your dreams crushed right before your eyes.” He pauses, sniffling. “Do you realise? Your dream is now my dream, and I would rather kill than to see it taken away.”

“By killing me?” John asks weakly, now clutching a nearby chair for support.

“It can all be avoided if Sherlock takes the fall.” Shakily, Sebastian sets down the rifle and looks down at his hands. “He loves you, John. He might do it to save you. If he falls, the story will be published without our accounts included. If he doesn’t, and I don’t kill you, we’ll all be ruined. Do you understand?”

John heaves a shaky breath and looks at his donor, tears threatening to rise. Without another word, he rushes from the room and out the flat to hail a cab, ignoring Sebastian’s calls behind him.


	10. GGC (GLYCINE)

The final act. Oh, but of course. The suicide. The disgraceful death of Sherlock Holmes, fraudulent genius. One final act to seal Moriarty’s triumph.

“I can still prove you as a borrowed ladder,” Sherlock mutters, but it’s half-hearted. There must be something else at stake, or else Moriarty wouldn’t bother with the usual accoutrements of a borrowed ladder.

“Just kill yourself. It’ll take less effort,” retorts the Forger. “But let me tell you a little secret, give you a little extra incentive. Johnny-boy will die if you don’t jump.”

Sherlock’s eyes widen. Moriarty notices and grins, eyes twinkling as he walks around the stunned Identifier.

“Rather inevitable, wasn’t it? Neither can live while the other survives. If you live, in order to keep your name with the police you’d have to destroy him, wouldn’t you? Reveal him as a borrowed ladder. And if he lives, in order for him to keep on working as a surgeon he’d have to incapacitate you. You can’t lie for him forever, Sherlock. So I’ve made it easier. Either you take a long walk off the roof of this hospital, or Johnny-boy’s donor will shoot him in the head.”

“And you’ve blackmailed his donor to do so.”

“Obviously, with the promise to destroy any transactions in my records that will implicate him and Johnny,” yawns Moriarty. “Some people can be so damn gullible in their desperation.”

“You’re expecting me to die in disgrace to save John.”

“Isn’t that what people do for love?”

Sherlock walks over to the edge of the roof and looks down from the ledge, onto the pavement where an open-top lorry sits, and several people are gathered. Moriarty walks over and peers down as well, grinning.

“Looks like you’ve got an audience. But hey, your death’s the only thing that’s gonna stop Seb Moran now. He’s a good boy. He knows what he’s gotta do to protect him and his little pet.” He giggles. “So off you go. Jump to save Johnny. Lord knows I’m not going to call off his donor.”

And at that, Sherlock laughs.

“What?” Moriarty demands. “What’d I miss?”

“You’re not going to call off John’s donor? So there must be a safeword, isn’t there? I don’t have to die if I have you.”

“You think you can make me call off Sebby?”

“There is no limit on what I can’t do,” replies Sherlock, feeling more and more sure of himself as he steps away from the ledge, grinning at Moriarty. “I used to think that I couldn’t lie in my line of work, until I met John. And when it comes to him, I am prepared to do anything. Prepared to do what ordinary people can’t do.”

“But you _are_ ordinary, Sherlock. You’re on the side of the Valids.”

“So I may be. But I lied for an in-Valid, too.”

“Two sides of the same coin. Wonderful, Sherlock, wonderful. Well played.” Moriarty grins, extending a hand to shake Sherlock’s. “You aren’t ordinary. You’re me.” He pauses again, looking into Sherlock’s eyes. Without the disconcerting green colour contacts, his eyes shine beetle black against the glare of the morning sun. “Yes, as long as I’m alive you can save Johnny-boy.”

And before Sherlock can react, Moriarty has a gun out and pointed at himself. “Well, good luck with that!” cries the Forger as he pulls the trigger. Blood splatters everywhere; Sherlock reels back in horror as Moriarty falls to the ground, blood dripping out of both the entry and exit wounds. Moriarty’s black eyes now look heavenward, unseeing, and Sherlock turns around in shock and disbelief.

Down by the kerb John Watson emerges from a cab.

Sherlock reaches for his mobile and dials John’s number.

* * *

There aren’t many things that Sebastian Moran would fight for.

He’s by nature not a very sentimental man, but all of this has been a five-year process for him. Five years of knowing John Watson, imperfectly perfect John Watson.

John tries so hard to do good, tries so hard to be good. John has never known life as someone perfect, someone like Sebastian, and the effort it had taken for John to become Sebastian has taught them both what it meant to pay the price for perfection.

Sebastian is the fearless warrior, the courageous soldier of poets’ ballads. He is the hero – for most of his life he has gotten away with being loudmouthed, brash, arrogant. People find it charming, because people know he is perfect.

And then the shoulder wound shattered all of that quite literally. For the first time in his life, Sebastian tasted mortality. And he didn’t like how it robbed him of perfection.

But John, imperfect John! John had been born dying, with that heart of his. John had been born breathing, tasting, living mortality at every turn, every blink, every twitch. And yet that made him all the more eager to play with it, to figure out how to save lives.

Sebastian takes away lives. John gives them back. And Sebastian would take away John’s life if it means the best for him, if living beyond that meant that he would never be able to give back the way he did before. This much he knows as he sets up the rifle from his vantage point across from the hospital, looking down through his sight at John.

John’s on the phone, talking to Sherlock on the rooftop. Sebastian can’t hear what they’re saying, but the look of disbelief on John’s face suggests that Sherlock is playing the game to the letter. He’s confessing.

* * *

“It was all me,” Sherlock’s voice says from the other end, as John looks up at him from his spot across the street. “I am the real Forger. Moriarty was just a borrowed ladder.”

“What the hell are you on about, Sherlock?” John demands.

“I... invented...Moriarty the Forger.”

John’s breath catches in his throat. “No, Sherlock, shut up. You knew I was a de-gene-erate within seconds of meeting me.”

“No one could have been that clever. It’s not possible.”

“And who made you the authority on what’s possible?” demands John. “Look at yourself, Sherlock! You only see the flaws in yourself because that’s what they’ve brought you up to look for. Flaws. Flaws in me, in you, in every other person on this goddamned planet. You are clever, Sherlock. You are the most brilliant person I have ever known. I shouldn’t have to tell you that it’s possible, but for what it’s worth, it is.”

He can almost hear a choked laugh from Sherlock, as if he’s is struggling to hold down tears.

“I knew about you beforehand, obviously,” Sherlock says after a moment, evidently still intent on proving himself a fake. “I arranged for Moriarty to take you to meet Moran, so obviously I knew –”

John sighs, throwing all caution to the wind. “Does it matter anymore, Sherlock? Because if you were the Forger, then why did you choose to lie for me, of all people? There were so many other worthy borrowed ladders to protect, but you chose _me_.”

“People do silly things.”

“Now you’re just grasping at straws, Sherlock.” John lets out a little chuckle at that. “But in all honesty, it doesn’t matter to me anymore, even if you do turn out to be the Forger.”

“Why would you say that?” Sherlock’s voice is so small, so pitiful. John feels a great heavy something tug at his heart at that, at Sherlock sounding so _vulnerable_.

He sighs again. “Because either way you made my dreams come true. And that’s what matters.”

He can hear Sherlock’s sniffles on the other end. The Identifier is reaching out for him from the top of the building, and John finds himself reaching up as well, wanting to touch Sherlock once more and remind him that it’s fine, it’s _all_ fine, and in the end, everything is going to be fine.

“I have to do this, then,” Sherlock says after a moment. “If I don’t, you’ll… well, I can’t have this happen to you.”

“What do you mean?”

“This phone call... it’s my note.”

“Note?”

“Isn’t that what people do when they...?”

“When they do what?” John’s heart is racing again, preparing for the worst. His breath catches in his throat.

“Goodbye, John.”

A click. Sherlock hangs up. He tosses his mobile to the side now; his arms are outstretched – John’s heart speeds up even more; he needs now, more than anything, to be able to reach for him, to be able to save his life and protect him from the rest of the world.

 “SHERLOCK!” he cries, his voice full of so much raw emotion and pain and _oh dear god please don’t jump Sherlock please don’t –_

_Please don’t leave me all alone, Sherlock, I–_


	11. TAG (STOP)

There are many things Sebastian Moran never wants to see again.

John Watson’s shattered expression is one of them.

He wheels himself down the ramp from the lookout post, rifle discarded behind him. Already a crowd has gathered around the base of the hospital where Sherlock has fallen, where John sits with the man’s limp wrist in his hands, tears flowing freely down his face.

“We have to go,” Sebastian whispers, tugging at John’s sleeve. “Come on.”

“No...” John sniffles, like a lost child. “I need to save him. I need to; I’m a doctor...”

“There’s nothing you can do,” Sebastian soothes. “Let’s go home, Seb.”

“No!” John howls. “There must be something!” But already the paramedics have Sherlock’s body on a stretcher and are wheeling him away from the scene; John clings to the air where Sherlock’s wrists had been previously. Sebastian feels the sting of tears in his own eyes, but he wills them down to tug at John’s sleeve again.

“Let’s go, Seb,” he insists.

“No, you go on ahead,” John sniffles. “I’ll stay.” And there’s nothing Sebastian can do to prevent the other man from racing after the stretcher into the hospital, as if determination alone could bring Sherlock back, that perhaps Sherlock isn’t dead at all.

It’s all so John, to believe the best of the situation. To give life. For such an imperfect man, he is so perfect in other ways that it tugs at Sebastian’s heartstrings.

Guilt overwhelms him. He’s at least partly responsible for this. If only he’d stood up to the threats! If only he’d protected them better! Sebastian is a soldier, and yet he couldn’t even fight the fight to save his closest friend.

He isn’t worthy. This isn’t how the perfect man behaves. He should have been stronger. He isn’t worthy.

And in that moment when he hails the cab for Montague Street, Sebastian knows what he must do.

He flops into the cab and the cabbie folds up his wheelchair for him, and Sebastian laughs at himself for being so weak, for being so damn useless. Because that’s all he ever will be. He caved to blackmail, he nearly shot his friend, he even broke that friend’s heart, however indirectly. Useless, worthless Sebastian Moran, only good for lending out his genes.

There’s only one thing left to do. John won’t mind. He won’t miss him. After all, Sebastian’s managed to archive for him over two lifetimes’ worth of genetic material. John can go anywhere, do anything. He can live the life that Sebastian had taken for granted from the very beginning, the life Sebastian had thrown away when he walked in front of that Humvee.

Montague Street approaches. The cabbie carries Sebastian out and places him in his wheelchair. Sebastian pays him and wheels himself into the basement of his and John’s flat, intending on finding a pair of scissors and a card for his note.

“Two suicides in one day might be a bit too much for John’s heart, wouldn’t it?”

Sebastian blinks, and wheels himself around to see Sherlock Holmes, sitting at his basement table. Across from him sits Mycroft Holmes, tapping his umbrella idly against the linoleum.

“You seem shocked. Are you going to go fulfil your side of the bargain now? Moriarty’s dead.” Sherlock surveys Sebastian above the tips of his fingers. “Don’t.”

“We have all of his papers,” Mycroft adds, pulling out a large manila folder. “Including the transactions implicating you and John Watson.”

“Paper trails can be easily destroyed,” agrees Sherlock, holding out his hand. “Lighter?”

Sebastian hands over his lighter. He can only look on with wide eyes as Sherlock pulls out a series of papers with John’s name on them and sets them to the naked flame of the lighter. Slowly the papers yellow and curl; before Sebastian’s eyes they become nothing more than ash.

Sherlock lightly blows out the flame and smirks at him. “No one will ever know.”

Sebastian coughs, trying to regain the ability to speak. “How?” he asks after a moment. “How did you survive?”

“Good old-fashioned records fraud,” Mycroft sniffs. “Molly Hooper temporarily masked the profile of a recently-deceased in-Valid who was roughly Sherlock’s height and sported similar features. I merely had to drive the lorry away after Sherlock fell into it and pushed out the body onto the pavement. Some well-placed colleagues of mine took care of the rest.”

“Now I owe this overweight bastard a year’s worth of cake,” Sherlock adds scathingly, and while Sebastian might have chuckled at that any other day, he doesn’t do so now.

“Well?” he demands. “So you’ve escaped. How the hell are you going to explain that to John?”

“Yes, how are you going to explain that to me?” cuts in a new voice. Sebastian freezes.

John Watson is standing at the bottom of the spiral staircase.

* * *

At John’s voice, Sherlock turns. Out of the corner of his eye he sees the other two leave.

John walks towards him, almost as if in a trance. Sherlock gets up, meets him halfway. He reaches out and takes John’s hands, smiling nervously.

John shakes his head.

“I got your text,” he says. “ _Shut up, you idiot_? You utter _bastard_.”

Sherlock chuckles weakly. “Well, I –”

“Don’t need an explanation for that. You’re just an arse,” John replies, before throwing his arms about him and pressing their lips together, before driving Sherlock back against the counter of the table. He barely feels the pain, because he is overwhelmed with John – John, smelling faintly of hospital and blood but overwhelmingly of _John_ ; John, pressing their bodies close together as if all the air between them should not exist; John, whose contacts have fallen out somewhere between the hospital and Montague Street and whose real eyes are a rich burnt umber, mesmerising in their own right.

They break apart for air, and Sherlock takes the opportunity to admire John. Beautifully human, flawed John, who probably can’t see Sherlock’s face right now, whose heart is racing a mile a minute, whose life exists solely on borrowed time at this point. Sherlock’s overwhelmed by all of this affection he didn’t know he could feel.

“Your eyes are nice,” he remarks.

“Yeah, well. They can’t see a damned thing.” John gropes in his blazer pocket for his glasses, and dons them for the first time in years. With them he looks a bit strange, a bit comical. But Sherlock doesn’t mind too much.

“I’m sorry,” Sherlock says after a moment of shared silence. “For letting you believe... you know.”

“Just don’t let it happen again,” John replies, shrugging.

“I don’t think I’ll ever be able to,” Sherlock sighs. “Can’t go home again, you know? Now that I’m as much of a fugitive from society as you, I think it’s time we disappeared.”

“Go into hiding?”

“Nothing of the sort.” Sherlock smiles. “You know, Irene Adler isn’t actually dead. She faked her death, too. Faked the records. Now she’s travelling the world.”

“You want to travel the world.”

“I’d like to go to Sussex.” Sherlock smiles, pressing their foreheads together. “Quiet little cottage on the beach, near the chalk cliffs. You’ll write books, and I’ll keep bees. No one will ever bother us about our birth statuses ever again.”

“Sounds like a plan,” John replies, smiling.

“Mycroft’s already booked us the transportation. We have an old family house down there. All you need to do is pack.”

At that moment, though, Mycroft and Sebastian re-enter the room. “I’ll be travelling, too,” Sebastian says quietly, wheeling himself up to John and handing him an envelope. “Don’t open this until you’re in Sussex.”

“Thank you,” John murmurs, pocketing the envelope.

“I’ve archived for you enough genetic material for two lifetimes,” continues Sebastian, “on the off chance you’ll ever need to return to London. Mycroft’s agreed to move it all into Baker Street, for better access.”

Sherlock could have sworn he hadn’t felt this grateful to his brother in ages. He smiles, thin-lipped, at Mycroft, who nods in reply.

“Good luck,” Sebastian tells Sherlock, before turning to John. “And I still maintain that I got the better end of the deal.”

“You think you couldn’t have done this?”

“No. I had the genes, but never the passion. You brought that to me.” He smiles, sending a knowing look at Sherlock for that. “I wish you all the luck.”

“And to you, too, wherever you’re going,” John agrees, his voice thick with tears and emotion. “Hunt me a tiger, won’t you?”

Sebastian makes a half-choked noise at that; Sherlock’s pretty sure he’ll give up holding back his tears at any moment. Hand in hand, he and John turn and ascend the spiral staircase. Halfway up, Sherlock looks back to see Mycroft and Sebastian watching them go. Their keepers, letting them loose at last.

He smiles.

* * *

Sebastian is the only one left. Alone. This is what alone must feel like.

He could have sworn he had known alone before, after his failed suicide attempt, watching everyone he ever thought had cared about him slowly turn their backs. But no. That wasn’t alone. _This_ is alone.

This, the pressing solitude of the empty lab, with only the quiet humming of the refrigerators and incubators to keep him company. This, the utter vastness of a room in which he is the only living person. This, the quiet emptiness of his heart, which had recently been so full of worry and regret for John but now is softened, emptied, its contents stolen by Sherlock Holmes.

The in-Valids weren’t lying. That man is a true life-ruiner.

Sebastian laughs a little to himself at that thought as he wheels himself to the incinerator. Mycroft has had someone bring him back his rifle, the one he had left in the building across from Bart’s. The one he had nearly killed John with, the one that had served him well in Afghanistan but not enough to save his life.

The last emblem of the soldier. And Sebastian has never loved it more than he does now.

Sebastian hauls himself into the incinerator with the rifle, folding his pained and useless legs into the cylindrical chamber. No longer is this an act of penance for what he’s done to John. No, this is an act of love. By burning away Sebastian Moran, he will finally set John Watson free. The caged bird is the keeper, after all.

He closes his eyes and imagines John, holding Sherlock’s hand as their private helicopter takes flight and bears them down to Sussex, to the old Holmes family cottage, to happily ever after. He imagines John finally opening the envelope to see a simple white card with nothing written on it. Only a lock of hair.

The last piece of himself. The first emblem of genetic material. Lovers and friends used to keep locks of hair. Sebastian wants John to have this last piece of him to remember him by, to cherish him by. To keep a part of Sebastian with him forever.

John is happy now. He’s in a better place, with a better man. Sherlock’ll take good care of him. He won’t need to worry anymore.

With that thought, Sebastian Moran cradles his rifle close to him as he closes the door and waits for the flames. And as the fire begins to rise, he begins to laugh, free and joyous, for the first and last time in his life.

**FIN.**

**Notes for the Chapter:**

> I would like to acknowledge the dedication of my beta reader [whitefang3927](http://archiveofourown.org/users/whitefang3927/). She is absolutely amazing and provided some wonderful ideas.  
> For the scientific-minded, the chapter titles are the DNA codon/amino acid sequence for the hormone oxytocin.   
> Thank you so much for reading!


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